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PRACTICAL 

WIRELESS 



AUGUST 1964 



mn$ Fmi 2.V-S 





TRANSISTOR 
TUNER/CONVERTER 

1,2 or 5 TRANSISTORS 
OPTIONAL IF. STRIP 
PLUG-IN COILS 






^— 



PRACTICAL WIRELESS 



August, 1964 



RETURN- 


OF-POST 


SERVE C E 


ON CASH OR 


COD ORDERS 



• SPECIAL OFFER ! ! STEREO CARTRIDGES 

i;i>M ill 105 ■»>» -ri-o/Muno Cartridge. Complete with fixing 
bracket and b1 58/4 ODR PRICE 83/6- Post Tree 

S ILLUSTRATED LISTS 
istrated lists. »u-.j available on LOUDSPEAKERS. TAPE DECKS. 
TEST GEAR. GRAMOPHONE EQUIPMENT AMPLIFIERS 
Any win be sent free upon request. 

AMPLIFIER KITS 

tocks of all components for the Mullard 510. Mullard 
and 3 Valve Pre-amp. Mullard Stereo. Mullen 
detailed list on any of these sent upon request. 

Manual. All Mullard Audio Circuits In "Circuits for 
J/fi. Post free 



LATEST TEST METERS 



wo M.piii-i - Mark ii 
wo Mmii'l ; Marh M 
wo Multlminor Murk 1 

1 . M K. I 1*1(1 

t.M.K. UTiS 

T.M.K, \Ii. del 500 

I W I.OIt MODEL \ZJA 



Cash Prfc 
£24. 0.0 
£21. 0.0 £4. 4.0 

£9.10.0 

£3.19.6 

£5,19.6 



£8-19.6 £1.15.6 
£10.10.0 £8. 2.0 



Hire Purchase 
Deposll 
£4.16.0 12 ol £1.15.3 

3 or £1.8.0 

3 of " 

13 '.i 



£1.18.8 
&. 8.8 

£1.15.6 



Bl.11.4 

13/8 

15(8 



11 de above supplied free on rer$ . 

I urrent produ 
not to b* confused ii!:h Government ■■: 

#TAPE RECORDING EQUIPMENT 

1 VIM DEI KS Hire 

Cash Price I v/Pmt*. 

« <H I VKO SI I l)l<). Inf. -si 
model. Two truck. Bradmatii 

Hearts £10.19.6 £2. 3.6 12 or 16/4 

i-'mir Track, Miiiri..ii Beads £17.17.0 £3,12,0 12 or 28/2 

MV1UT\ TAPE AV1IM.IFU.K KITS 
l;i|n- \ni|iJJIii>r» 

liaro H311-V 2-Track £11.11.0. 8311-4-V 4-Tnu k £12.12.0. 
Tape re- Unpllfler* 

' i- 2-Track £8.8.0. 8319-4-CP 4-TraclC £9.9.0. 
iftly for mounting 8319 Pre-Amp under Collaro 

( arrxiiK i nsm with speaker. For Collaro Deck and 8911 Amplifier. 

II. i*. TERMS available on decks, amp. and cai 

# GRAMOPHONE EQUIPMENT 

ALL LA Hire Purchase 

ALL! Cash Price Deposit Mthlv/Pmts. 

RECORD CHANGERS 
«. AIU5 \ltl» VI TOM. CM 



' PU> 

I. Vlflt.Vltl) VI HISMM 

De-luxe VTBlMonoPU) 

(. Milium vi losi.ivt 

v l(i Steieo/Mon 
tt.s.tt. I Vll (TC8 Mono PU) 
It.s.li. I'AU Monarch 

}eereo/LP/78) 
U.S. It. IV r, TC8 MonoPU) 



£6.17.6 £1.12 ' 



n 



£11. 9.0 £2- 6.0 12 or 16/11 



£12. 5.4 
£6.15.0 



£2- 9.4 
£1.10.0 



Dor 



£7.15.0 £1.18.0 
£7.15.0 £1.18.0 



£8.15.0 £2. 6.0 Sol 



IS/- 
£1 



£1.2.0 
£1.2.0 



£1.4.0 
See ■>!!! 



II sit. i vi.l 

■ above can be [supplied Ut sli-reo working. 
i'.ine Euulpmem List for details 

JASON F.M. TUNERS 

we stock all parts needed for the construction of these excellent 
All parts can be supplied separately but we can offer 
attractive reductions In j: -is are purchased at same 

time as follows: 

mil. £6.12.6: FSTR(l<*ss power), £7.15.0. 

ran wild power). £9-12.6: Klin less power), £9.9.8- 

I VII:: widi \nn\ en, £11-7.6. Meri-urv 'l. £10.14.8. 

I I V )■>. £14.12.6. 
ircaase Terms available. Ask for list. 

HI-FI LOUDSPEAKERS 

I.OOIIMANS: Axietce Sin.. £5.5.7: Axiom 101 n, £6.5.11: 121n 

W ' -i'l. £10-17.4: 12in. Axiom 3111, £15.4.6: 12in Audlom 

-.1 lta>s. £9.2.8: 121n. Audlom si Bass. £14-7.8: Treba* tweeter. 
£610. 2: XOSOBO Crossover unit, £2.0.11. 

WIIITELEV; IIFIOIG Win. £7.7.0; IIFI0I2 Win,, £4.12.0: 
HIMii Bin.. £6.6-0: TSIfl ain., £5-19-6; Tin Tweeter, £4.12.0: rr..i 
rweeter, £1-12.3: CX3000 Crossover unit, £1,13-3: CXliWl 
( roNttover unit. £2.2,0. H.P. Terms available on all speakers. 



MlS, )LTD 



WATTS RADIO ( OR 

54 CHURCH STREET, WEYBRIDGE, SURREY 

Telephone Weybrldge •17551. 
■ oote: Postal business only from Cats address, 
Callers welcome by appointment. 
CLOSED FOR ANNUAL HOLIDAYS: AUGUST 1ST TO 22N0 




SOLDERING INSTRUMENTS 
AND EQUIPMENT 




DESIGNED FOR 
THE AMATEUR'S 
RADIO STATION 



ILLUSTRATED 

List No. 70 | BIT 

IN 
PROTECTIVE 
SHIELD 
List No. 68 



for catalogue apply direct to: — 

Sales and Service Dept., 

ADCOLA PRODUCTS LTD., 

ADCOLA HOUSE, 

GAUDEN ROAD, LONDON, S.W.4 



Telephones 
MACaulay 4272 & 3101 



Telegrams 

SOLJOINT LONDON SW4 



August, 1964 



PRACTICAL WIRELESS 



297 



-crfCjftede anoL 



Man — Sat. 9 a.m. 

— 5.45 p.m. 

Wednesday I p.m. 



fuisulredA 



Special 24 Hour 
/^f/W^0L Egress Mail 

wWr\^UrW V^^ Order Service 



ACS'PEN 

is*e 

AC2/PEN 

DD I9'6 
AC TP 29'- 
AC/VPl-5-7 
15'- 



AZI 

AZ3I 

B36 

CIC 



15'. 

I3'6 

9'- 

10'. 



CCH35 20'- 

CL33 I2'6 

CYI 

CY3I 

D77 

DAC32 

DAF9I 

DAF96 

DCC90 I2'6 

DF33 9'6 



15'- 
126 
41- 
9'6 
5'- 
6'6 



DF9I 

DF92 

DF96 

DH63 

DH77 

DK32 

DK91 

DK92 

DK96 

DL33 

DL35 

DL91 

DL92 

DL93 

DL94 

DL96 

EASO 



3'* 
7'- 
6'S 
*J- 
7>- 
II'- 
5'6 
7'- 
7'6 
8'6 
10'. 
7'- 
5'- 
7'- 
71- 
6'* 
21- 



EABCSO S'6 

EAC9I 4'- 

EAF42 

EB34 

EB4I 

EB9I 

EBC3 

EBC33 

EBC4 



EBC8I 

EBF80 

EBF83 

EBF89 

EBLI 

EBL2I 

ECC3S 

ECC40 

ECC8I 

ECCB2 

ECC83 

ECC64 



9'6 
2'6 
6'- 
41. 

21'- 

S'6 
8 6 
10'- 
7'6 
8'- 
7'6 
21'- 
21'- 
8'- 
15'- 
4'- 
5'- 
5'- 
6'* 



ECC85 

ECC88 

ECC91 

ECFBO 

ECF82 

ECH3 

ECH2I 

ECH35 

ECH42 

ECH8I 

ECH83 

ECL8Q* 

ECL8I 

ECL82 

ECL83 

ECL86 

EF6 

EF9 

EF22 

EF36 

EF37 

EF37A 

EF39 

EF40 

EF4I 

EF42 

EF50A 

EF50E 

EF80 

EFS5 

EF86 

EFB9 

EF9I 

EF92 

EF95 

EF98 

EFI83 

EFI84 

EK32 

EL3 

EL32 

EL33 

EL34 

EL35 

EL37 

EL38 

EL4I 

EL42 

ELS I 

EL84 

EL85 

EL90 

EL9I 

EL9S 

EM80 

EM8I 

EM84 

EM8S 

EY5I 



7'6 

I2'6 

3'- 

7'6 

8'6 

II '6 

II'- 

126 

9'* 

7'- 

86 

*'* 

ID'- 

9'6 

10'6 

9'6 

21'- 

21'- 

14'- 

4>- 

8'- 

8'- 

4'- 

15'- 

8'- 

10'- 

3'6 

3'- 

5'- 

5'- 

7'- 

8», 

4<- 

4'- 

5'- 

10'- 

8'- 

8'- 

a '6 

21 '6 
4'6 
12 6 
14'- 
10'- 
I7'6 
17'6 
9'4 
9 '6 
I2'6 
*'- 
10'- 
8'6 
4'- 
10 '4 
8'6 
B'6 
8'- 
10'- 
7'6 



EY8I 

EY83 

EY86 

EY91 

EZ35 

EZ40 

EZ4I 

EZ80 

EZ8I 

EZ90 

El 148 

FC2 

FC2A 

FC4 



S'6 
I2'6 
7'- 
3'- 
6'- 
7'. 
7/- 
S'6 
S'6 
4'* 
2'- 
15'- 
I7'6 
15'- 



FW4 S00 9'- 
FW4 800 9'- 
GZ30 10'6 



7'6 
7 '6 



7 '6 
9'- 
7'- 
7 '« 

ll'i 



GZ32 
GZ33 
GZ34 
GZ37 



10'6 
I9'3 
I3'6 
I9'3 



HABC80 10'- 
HL4I 8'- 

HL4IDD 8'6 
HL92 8'6 
HLI33DD 

9'6 
HN309 25'- 
IW4/350 10'- 
IW4 500 10'- 
KT33C 8'- 
KT36 



PABCB0 13'- 
PCC84 7'- 
PCC85 9'6 
PCC88 I2'6 
PCC89 B'6 
PCF80 
PCF82 
PCF84 I2'6 
PCF86 I2'6 
PCL82 
PCL83 
PCL84 
PCL8S 
PCLB6 
PENA4 I9'6 
PEN4DD 

22'6 
PEN4VA 

I7'6 
PEN36C 

20'- 
PEN4S 10'- 
PEN4SDD 

25'- 
PEN4* S>- 
PEN4SDD 

20'- 
PEN DO 4020 

20'- 



T4I 15'- 

TDD4 12'* 

TDDI3C 

I7'6 
TH4I 
TY86F 
UIO 



KT6I 
KT66 
KT76 

KT8I 



17'* 

9'6 
I7'6 
10'- 
8'* 



KTW6I 8'- 



PL33 
PL36 
PL38 
PL8I 
PL32 
PL83 
PL84 
PL820 



15'. 

1 2 '6 

18'- 
7'* 
7'* 
7'6 
8'- 

18'- 



L63 

LNI52 
LN309 
LZ3I9 12'6 
MKT4 I7'6 
MS4B 
MVSPEN 

17'6 
MVS/PENB 
51 



5'- 

6'fi 
9'- 



176 



PM24M I3'6 
PX4 IS 1 



MUI4 
MX40 

NI8 

N37 

N78 

N 1 08 

N308 

N339 

N369 

OD3 

OZ4 

P2 



9'. 
IS'. 

8'- 
14'- 
22'6 
26'- 
18'- 
30'- 
10 '6 

S'- 

5'- 
10'- 



PX2S 
PY3I 

PY32 

PY33 

PY80 

PY8I 

PY82 

PY83 

PY88 

PY800 

PZ30 

QS9S 10 10' 

QSI50,I5 

10' 



25'- 
15'- 
I0'6 
I0'6 
7'6 
6'6 
S'6 
8'- 
10'. 
10'- 
15'- 



UI2 

UH 

U22 

U24 

U25 

U26 

U3I 

U3S 

U37 

U47 

USO 

US2 

U76 

U78 

UI4S 

UI9I 

U25I 

U28I 

J282 
! U30I 

U329 
IU339 
IU403 
I U404 

USO I 

UABC80 S'6 

UAF42 8'6 

UB4I 

UBC4I 

UBC8I 10'- 
I UBF80 7'6 
1 UBF89 7'- 

UBL2I 20'- 
, UCC84 II '6 

UCC8S 7'- 

UCF80 I2'6 
! UCH2I 20'- 

UCH42 8'6 

UCH8I 7'- 

UCC82 9'. 

UCL83 II '6 

UF4I 7'6 



20'- 

I2'6 

91- 

9'- 

9'- 

8'- 

21'- 

II'- 

II'- 

9'- 

17'6 

1 7 '6 

7'- 
41- 
6'6 
4'6 
10'6 
I3'6 
15'- 
15'- 
19 '6 
IS'6 
15'- 
I3'6 
10'- 
10'- 
I9'6 



UMBO I0'« 
URIC 15'. 



UU6 

UU8 

UU9 

UYIN 

UY2I 

UY4I 

UY8S 

VP4 

VP4A 

VP4B 



17 6 
15'. 
7'6 
I2'6 

IS '6 
7'« 
«'- 
15'- 
15'- 
IS'. 



VR 105/307'. 
VR 1 50/30 7' 
W6I II' 
W76 
W77 
W8I 

waiM 

X4I 



5'- 
41. 
61- 
61- 
22'* 



X6IM I2'6 
X65 1 2' 6 



7'6 
8'6 



R2 
i RI6 

RI9 
R20 
SP4I 
SP6I 



10'. 

I7'6 

16'. 

16'- 
3'6 
3'6 



UF42 
UF80 
UF85 
UF86 
UF89 
UL4I 
UL44 
UL46 
UL84 
UL85 



7'6 

7'- 

7'6 

12 6 

6'- 

8'- 

20'- 

I4'6 

6'- 

7'6 



X76 

X76M 

X78 

X79 

Y6I 

Y63 

Z63 

Z66 

Z77 

ZI52 

IA7 

1C5 

ID5 

ID6 

IH5 

IL4 

INS 

IRS 

IS4 

IS5 

IT4 

IU5 

2P 

3A4 

3A5 

3Q4 

3Q5 

3S4 

3V4 

5U4 

5V4G 

5Y3G 



126 

I2'6 
26'. 
40'- 
10'. 
10'. 
7'6 
10'- 
41- 
5'- 
II'- 
10'- 
8'6 
10'. 
9'6 
V- 
»'6 
5 '6 
7'- 
5'. 
3'6 
5'9 
22'6 
S'- 
I0'6 
8'- 
»'- 
5'6 
7'- 
4>- 
7'9 
4'6 



5Y3GT S'6 

5Z4G 7'6 

5Z4GT 8'6 

6A7 9'- 

6A8G 8 '6 



6A8GT 


3 '6 


6AC7 


6'- 


6AK5 


5'- 


6AL5 


4'- 


6AM5 


5'- 


6AM6 


4'- 


6AQS 


6'6 


6AT6 


4'- 


6AU6 


9'- 


6BBG 


2'6 


6BA6 


6'- 


6BE6 


6'. 


6BG6G 


IS'- 


6BJ6 


T- 


6BQ7A 


12 '6 


6BR7 


10 '6 


6BS7 


12 '6 


6BW6 


9>- 


6BW7 


»'- 


6C4 


3'6 


6C5GT 


8'- 


6C6 


6'6 


6C9 


I2'6 


6CD6G 


25'- 


6CH6 


10'- 


6CW4 


16'- 


6D2 


4'- 


6D6 


56 


6E5 


10'- 


6FI * 


10 6 


6F6 


5'9 


6FIZ 


4'- 


6FI3 


10'. 


6FI4 


10'. 


6FI5 


I2'6 


6FI9 


12 '6 


6F23 


10 '6 


6F25 


I6'6 


6F26 


I3'6 


6F33 


5'6 


6H6 


2'- 


6J5 


5'6 


6JSG 


4'4 


6J5GT 


5'- 


6J7 


7'6 


6J7G 


5'- 


6J7GT 


7'6 


6K7 


7'6 


6K7G 


2'- 


6K7GT 


7'6 


6K3 


9'6 


6K8G 


4'- 


6K8GT 


9'6 


6K25 


I7'i 


6LI 


10'- 


6L6 


7'6 


6L7 


10'- 


6LI8 


10'- 



6LI9 15'- 

6N7GT 9'6 
6P25 10'A 
6P28 I2'6 
6Q7 9'6 

6Q7G 6'- 
6Q7GT 8'6 
6SA7 7'- 



6SC7 
6SF5 

6SG7 
6SH7 
6SJ7 
6SK7 



8'6 
10'- 
7'- 

«'- 
616 

5'6 



6SL7GT S'6 
6SN7GT S'- 
6SQ7 8'6 
64UGT 10'- 
6U5G 7'6 
6V6G 
6V6GT 
6X4 
6X5G 
6X5GT 8'6 
6'30L2 I2'6 
7B5 



I2Q7GT 6' 

I2SA7 8'6 

I2SJ7 

I2SK7 

I2SL7 

I2SN7 

I2SQ7 

I4H7 

I4R7 

I9AQ5 

I9BG6G 15'- 

20DI 10'- 



8' 

6'- 

8'- 
10'- 
12'- 
10'- 
21'- 

8'- 



4'- 
8'. 
4'6 

S'- 



7B7 
7C5 
7C6 
7D5 
7D6 
7D8 
7H7 
7S7 
7Y4 
8D3 



I2'6 
8'6 
8'- 
8'6 
15'- 
15'- 
IS'- 
6'- 
17'* 
6'6 
4'- 



20D2 

20F2 

20LI 

20PI 

20P3 

20F4 

20P5 

25A6 

25 L6 

2SYS 

25Y5G 

25Z4 

25 Z5 

25Z6 

27SU 

30CI 



21'- 
17'* 

22'* 

IS'- 

24'- 

20'- 

20'- 

8'- 

8'- 

8'- 

8'- 

7'6 

8'- 

8'* 

19'* 

9'- 



I7'6 
10'- 
I2'6 



9BW6 I2'6 
IOC I I2'6 
I0C2 
I0F1 
I0F9 
I OLD It IS'- 
I OP 1 3 IS'- 
I0PI4 19'- 
1 IDS 23'* 
I2A6 *'* 

I2AH8 II'- 
I2AT6 7'* 
I2AT7 5'- 
I2AU6 I7'6 
I2AU7 5'- 
I2AX7 
I2BA* 
I2BE6 
I2BH7 10'- 
I2J5GT 4'- 
I2J7GT 8'6 
I2K7GT 5'- 
12K8GT 10'- 



5'- 

m 

T6 



30CIS I2'6 
30FS 10'- 



30FL1 

30LI 

30LIS 

30P4 

30PI2 

30PI6 

30PI9 

30PLI 



I2'6 
8'6 
II'- 
18'- 
10'- 
9'- 
17'* 
IS 



30PLI3 12'* 
30PLI4 I2'6 
35A5 15'- 
3SL6GT 8'* 
3SW4 *'* 
3SZ3 15'- 
3SZ4 *'6 
35Z5 8'6 
4ISTH 22'* 
42 I2'6 

50C5 10'- 
50CD6G 

30'- 



50L6 

75 

78 



S'6 
£'- 
7'fc 
7'6 

85A2 12'* 

iSSBT 30' 

807A 

807 B 



9'6 
9L 



COMPLETE VALVE LIST FREE WITH ORDER 



METAL RECTIFIERS 

RMI 7'6 HAS* 23'- 1 6 RD 2-2-8-1 12'- (FCI42) 

RM2 8'- 14A97 26'- 1 6RE 2-1^-1 '10'- (FC150) 

RM3 10'- I4AI00 28'- I, RA 1-1-8-1 5- (FCH8) 

RM4 I7'4 l4RAI-2-3-2 2l'-(FC30l> URA I-I-I6-I 7'- (FCN6) 

RM5 I9'4 1 4RA I -2-8-3 IS'- (FC3 I ) I iRD 2-2-8-1 l*'-(FCI24) 

TERMS OF BUSINESS C.W.O. or C.O.D. 
4 2 PACKING CHARGE ON ALL C.O.D. 
ORDERS. POSTAGE 6d. per VALVE 





BRAND NEW TRANSISTORS 


OC35 


10'- 


OC72 8'- 


OC8ID 5'- 


OC42 


*'. 


OC74 8'- 


OC8lm/pr I2'6 


OC44 


5'. 


OC75 8'- 


OC82 61- 


OC45 


5'- 


OC77 8»- 


OC82D 6'- 


OC7I 


5'- 


OC8I S'- 


OCI70 «'- 






SIL1CON REC 


EIVERS 


400 volts 3S0 


mA 


7'6 each 



SETS OF VALVES 

I R5, IS5, IT4, 3S4. 3V4 Set of 4. 17'- 

DAF9I. DF9I. DK9I. DL92. DL94 Sec of 4. 17'- 

DAF96, DF96, DK96, DL96 Set of 4, 25'- 



R ST VALVE MAIL ORDER CO 



211a STREATHAIVI ROAD MITCHAM SURREY 



J 



PRACTICAL WIRELESS 




FREE OFFER 

ELECTRIC 

SOLDERING IRON 

with the 

POCKET 

MULT I METER 
S*s item No. 7 
far lurcher detaib 



BARGAINS 



1. CTLD08 A.M, P.M. PERMEABILITY TUNER FOE ALL TBAHSISTOR 
OPERATION. Slit 24. i ijln. upprox. By famous manufacturer. AJ1. 
I.F. 470 Ec's, PJI.-JLP. 10.7 Mc/s. A.M. coverage from 1G20 Ktj6-f.28 
Kc* F.4I. coverage 108 Mi:;VMS Vein Llicuil diagrams 2/6. PKEE 
with Tuner, 88/-, 1st, 2nd, 3rd A.M. I.F/s. 12/6 set. 1st. 2nd 3rd 
and -tth F.M, UVs 18/8 set. V-H.F. Oso, choke, 1/.. AJL I.F. 
trap, 1/tv A,tf. 11* and A-F, IIS, «/- each. All the above Ms the 
Mh" end of us AM; I'M receiver oar radio, etc, The above six items 
purchased together, £4.10.0. 

2. iU INDOOR AERIAL. Complete with stand, fully extendable, can 
also be used tor 405, ITT, BBC and FM. 19/8, plus 1/- P. & P. 

X h.O.ID.0. POCKET MULTI-METER KIT, i'ln, moving coil meter 
scale calibrated In A.C./D.C. volts, ohmi and miliiampa. Voltage 
mu ire A.CJu.0, 0-00, 0-100, 0-200, 0-500. Mllllampi U-10, 0-1000, 
Ohms rsagSh 0-10,000, 0-100,000, 19/8. F, *. P, IK Wiring diagram 
1/-, free with parts. 

4. SIGNAL GENERATORS: Cash 17,8,0 or SO/- deposit and 8 month J j 
payments of 81/8, P. A P. 1/8. Ooverafie 100 Ke/s to 100 Me/i? on 
fundamental* and 100 Mc/s to Sou Mc/s on harmonics. Case 10 I 
BJ I Situ, Three miniature valves and Metal Rectifier. A.C mitai 
200/250V. InLei-nai modulation of 400 e.p,s. to a depth of 30 per cent. 
Modulated or unmodulated K.K. output oontmuouxiy variable 100 
tnultlvolta. C.W. and mod. awiteh, variable ij, output. lUfic eye 
an output uill._al.ji, Accuracy 2 per cent, 

0. SIGNAL GENERATORS. Cash M.6.0. P. A F. 8/6. Coverage 
120 Kefs to 84 afc/a, Cmc 10 x 64 * 44m. Size of scale 04 x Sitto. 
II valves and recti tier. A.C mains 2MO-2S0c, Internal modulation 
of 440 biu. to a depth of 30 per cent, modulated or unmodulated 
H.F. output continuously variable 100 niilli volts. UW. and mod. 
switch variable A.F. output and moving ooli oat put meter. Accuracy 
±3 per cent, 

0. CTLDOR PERMEABILITY TTSJfER medium and loaf wave Tuner. 
Sine 8 x 2 x lfm. appro*. Coverage 190-540 Metres, 1250-2000 mcim 
jg. I.F. 470 Kc/s. Price 19/8, F. * P. 1/8. 

i" J POCKET MULTI-MITER, Hum S( x 2| x Ifln. Meter she S| x Ilia. 

^ f riemdtivfty 1.000 O.P.V. on both A.C. and D.C. A.C. and D.C. volta, 
0-15. 0-150, 0-1,000. D.C current 0-150 ma. Resistance 0-100K a. 
Complete with tent prods. balUry and full instructions, SI/-. P. A P. 1/6. 
FREE GIFT tor Hmited period only, Su watt Electric (kidertng Iron 
value It/- to every purchaser of the Pocket Multi-Meter. 

S- CHANNEL TUNER UP, 10-1!) Mere. Continuously tunable from 
174-216 Mc/i. Valves required— PCP80 and FCC84 (In aeries). Cover 
rVBv and ITA rantics. Also Police. Ftre and Taxis, etc Brand new 
by famous maker. 10/-. F. * F. 31-, 

9. The MOTORISTS' REV. COUNTER, Kit oi parts comprising 27b degree 
Sin. moving coil movement. Manufacturer*! present price of this move- 
ment would be at least 47. Complete with full Instructions and circuit 
diagram, Scale calibrated up to 8000 r.pjn. Can be used with any 4 
or 8 cylinder car. (9/6, plus 116 P. 4t F. 

10. BAB, MONARCH UA14 WITH FULL-PI BXAD. 4-rpeed, slays 10 
records, 12in., lOln. or Tin. at IE, S3, 45 ot 78 r,p.m, Intemiixai 
71n.. lOin. and 1210, records of the aaiue speed. Has manual play 
position: colour bravo, Dimensions: lfi r x lOfin. Hpece required 
above baseboard 4iiu., below baseboard 2{tn. Pltt«d with Full-Pi 
turnover crystal be«d, fi.19.6. P. * F. fl/6. 

11. 80 MICRO-AMP METER movement by world famous menuJaeturcr. 
Sue 3 x 25 in.. 50/- posi (roc 

12. C-wuu PtftH-PTTLL 8 VALVE AMPLIFIER slai METAL REOT1FTER. 
A.C. mains 3O0-25Q v. 8ise 10 ( i (I i 2tin. B varvea. Fur use 
with all makes aud types of pick-up and mike. Negative feed back- 
Two input, mike and gram, and controls for same. Separate controls 
lor Bass and Treble Eft. Response flat from 40 cycles t« 15 ko/a. 
2 dB down to 20 kc/a. Output S watti at 5 per cent total distortion. 
Mote level 40 dB down aU hum- Output tmnsforiaer tapped for 3 and 
15 ohms speech colls. For use with 3td. or L.F. records, musical 
inatrumeul^ such as guitars, etc 4 ul table for small halls. fS.19.fi. 
P. ft P. lh. Crystal mike to suit, It/-. P. A P. 21- Sin. P.M. Bpeaksr 
to suit, 18/6, P. & P. 2J-. 

13. FLUORESCENT LIGHT KIT. 40 watt fluorescent lighting kit com- 
prising Siemens Choke, 2 Bl-pln holders, starter holder and starter, 11/fl, 
plus if- V. A r. 

14. FIXED FREQUElfCT SIGJtAL 0EHXRAT0R. Cryst*) control m metal 
case, size ltzOx Oln, Incorporating two FClft valves, mains trans- 
former, metal rectifier, choke. Indicator lamp, crystal and numerous 
components. Modulated and unmodulated nut put socket. Originally 
nsed for I.'l'.v. rraquencles, Brsnd new. S9/6. plus (!.'- P. ft P. A.C. 
Mains 200-25U volts. 

RADIO & T.V. COMPONENTS (ACTON) LTD. 

21 b High Street. Acton, London, W.3. 

All enquin«.» S.A.E. Goods not deipatchesd outside U.K. 
Shop Hour* 9 sum. — i p.m. Early closing Wednstsday. 



August, 1964 



PRACTICAL WIRELESS 



299 



mwLwmt 



\J^€e^€x^t^i^^i^e^t^ 



FROM R. & T. V. LTD. 




COMBINED PORTABLE & (AR RADIO 

The Radio with the STAR features 
Ay 1 SPEAKER 
■fc 7-translstor superhet. Output 350mW. 
■Jc Two-tone grey wooden cabinet, fitted handle with 

silver coloured fittings. Size \2£ x 8£ x 3|in. 
■^ Horizontal tuning scale, size ll| x 2|in. in silver 

with black lettering. 
*fc All stations clearly marked. 
■^ Ferrite-rod internal aerial. 
■£ |.F. 470 Kc/s. 
-fa Operated from PP9 battery. 
-fa Full comprehensive instructions and 

point-to-point wiring diagrams. 
■^ Printed circuit board, back printed 

with all component values. 
•£ Fully tunable over medium and long 

waveband. 
-fc Car aerial socket. 
■jc Full after-sale service. 

RADIO & TV COMPONENTS (ACTON) LTD 21C High St., Acton, London W3 



ONLY 

£4.19.6 



Plus S'6 P, & P. Parts list & circuit 
diagram 2'6, FREE with parts. 
Goods not despatched outside U.K. 
All enquiries S.A.E. Terms C.W.O 



Viirw111.il 1 j iHiiun; u. i l# xil ni 

Open 9 a.m. -6 p.m. including Sots. Early closing Wed 



GUITAR AMPLIFIERS WITH TREMOLO 

HIGH FIDELITY UNITS WITH UI.TRA UNBAR PUSH 
PULL OUTPUT 

We believe these amplifiers to be the most comprehensive 
to be ottered at such reasonable prices. 

Five jack 
socket In- 
puts, four 
with separ- 
ate mixing: 
volume con- 
trol--:, and 
me Input 
' 'a tralg h t 
through". 
Ail inputs 
are of 

very high 
sensitivity, 
only 10 
millivolts 
input is 

required for 
full output, 
making 
them riii it- 
able for all 
types f (ful- 
tars and 
microph- 
ones. Separ- 
ate Bass 
and Treble 

controls, giving a wide range of lift and cut. Separate master 
gain control. Tremolo speed and depth controls. Jack socket 
for remote tremolo switching. Outputs for 3 and 15 ohms 
speakers. Valves used in the 30 watt amplifier ECC83. ECC83, 
EL34 EL34 GZ34. In the 15 watt amplifier ECG83. ECC83, 
ELS4, EL84 EZB1. An extra valve ECC83 is used in the tremolo 
circuit. Supplied as a lit or factory built. The kit includes 
full step by step Instructions and all parts, with fully punched 
chassis. The chassis is complete with baseplate and Is solidly 
made of 18 gauge steel, finished silver grey hammer. Size 
12x.8x.6i inches high, 

30 watt' with tremolo. Kit £12.10.0- Factory built £15.10.0. 
30 watt, less tremolo. Kit £11.10.0. Factory built £14.10-0. 
15 watt with tremolo. Kit £9.10.0. Factory built £12.10.0. 
15 watt less tremolo. Kit £8.10.0. Factory built £11.10.0. 
Add carriage 10/- any amplifier. Send Cor free descriptive leaflet. 
STROUD -\UDiO. Paganhffl Lane, Stroud, Glos. Stroud 7B3 




BARGAINS FROM 

BROADWAY ELECTRONICS 



llin. ALTHAM SPEAKER with built-in tweeter, 3 ohm or 
IS ohm, 7,000 Gauss Magnet. Only 29'6, postage 3f6. 
THE FAMOUS BM3 XTAL MICROPHONE witf, 
lanyard, 32'6; table stand 9'6 extra. Xtal insert 7'3. 
GUITAR PICK-UP complete with clip and screened lead. IS'-. 
3-WAY PUSH-BUTTON UNITS, each button operates a 
4-pole, 2-way switch, 4'6, 

BARGAINS IN TRANSISTORS. Mullard complete RF Packs 
OC44, two OC4S, I2>6; AF packs OCSId, two OC8I, I2'i; OC44, 
3'*; OC45, 3'-; OC7I. V&; OC72, 3'-; OA8I diode, 2'3; AFI 14, 6'6; 
AFI 15, 6'«; ORPI2 Light Cell, 7'6; OC29, I2'fi. 
TRANSISTOR ELECTROLYTICS. IjaF, 2u.F, 4uF, 5u.F, 8(iF, 
IO;j.F, l6[iF. 32hF, 50u,F, IQ0u.F, all at 15V, I '3 each. 
McMICHAEL TELESCOPIC TV AERIAL. 23m. extends to 
45in. Fitted with Co-ax Plug, wilt suit any set, Only 7'6. 
CARTRIDGES. Will fit most pick-ups, Acos GP67-2G, medium 
output. 15'-; GP 59-5 high output, 15'-. BSR Stereo. £1. 
EARPIECES. With cord and 3-5 mil plug, 8 ohm magnetic, 3'-; 
250 ohm. 4'-; Xtal. 4'-; 180 magnetic with clip, 6'6; 3-5 mil plugs 
with nice long shank, 3'-: screened. A'-. 

ATTRACTIVE TWO-TONED CABINET, Mx6xS. room lor 
small amplifier, fitted with ex TV Sin. speaker. Only I9'6, post 2*6. 
TOGGLE SWITCHES. Single pole with on-off plate, 1'6, with 
screw terminals, 2'9. 

TERMS: C.W.O. OR C.O.D. 

BROADWAY ELECTRONICS 
92 MITGHRM ROAD, TOOTING, S.WJ7 

Phone: BALham [3934] 
(four mlnutetfrom Tooting Broadway Under? round Station) 






300 



PRACTICAL WIRELESS 




August, 1964 



TECHNICAL 
TRAINING 
in radio 
television and 
electronics 

Whether you plan to have your own business, to 
become an electronics engineer, to take up a career in 
industry, or to brush-up your knowledge and study 
new developments, transistors, etc., an ICS 
Course will help you to success. You learn at home 
n your own time, under expert tuition, Moderate 
fees include all books. 

EXAMINATION COURSES FOR: — 



0. & G. Radio 
and 

TV Sort-icing Certificate 

(R.T.E.B.) 



G. & G. Radio 
Amateurs' Exam. 

(Amateurs' Transmitting 

Licence) 

P.M.G. Certificate* in 

Radiotelegraph? 



Institution of Electronic and Radio Engineers, 

C. & G. Telecom. Technician's Cert. 

Gen, Cert, ot Education, etc. 



New practical radio construction courses 

Learn as you build the ICS way. Learn the 
theory of radio and electronics. Build a 5- 
valve, 2-waveband receiver, a transistor port- 
able and an A.F. amplifier. Build a signal 
generator and a multimeter as well, if you 
wish — two essential pieces of equipment for 
those engaged in servicing work. Three 
courses to choose from. 



Post 1 M/s Coupon TODAY*/ 



tor FREE book on 



career* in Radio, and full details of other ICS Course* 

Member of the Association of British Correspondent* Colleges 



INTERNATIONAL CORRESPONDENCE 
SCHOOLS 

(Dept. 171), Intertext House, Parkgate Road, 
London, S.W.I I 

Please sand book on... 

Name Age „ 

(Block Letters please) 

Address .........»...,,,.. 

Occupation up rum un m i 8.64 



INTERNATIONAL CORRESPONDENCE SCHOOLS 



EX-RENTAL T.V. SETS 



Send for list o f 
our range of other 
models. Demon- 
stration*; daily in 
our shop, from a 
large ■ election. 

12. months written 
guarantee. 

Channel* for all 

areat. 



I71n. 
£11.10.0 

Mln. 
£7.10.0 

C * rr - I7in. 10'- 
Personal Col- 
lection Adv isad^ 

IIBCtTA I'fltuhlnetl Loft au.i room aerials— Fn.in M/-. BBil, 
[.'lit' frmt aik.ur »nl«!.i— Frr.m 3T/a. SEND FOR FKEE I.lgT. 





REGUNNED TUBES 

Guaranteed I 
99/ 8 Year. Ins. and 
7« /R Carr. I0'6. Add 
10/0 IQf- refundable 
Mffl on OLD TUBE 
o8 /°(l 10° Tubes in 

stock.) 



EX-MAINTENANCE TESTED TUBES 
I7in. — 35'-. Hin. — 15'-. 

Carriage 5'- Satisfaction Guaranteed. 



TfclEPHONE 

^-~> HANDSET 

/^ 15/6 „r. 

tern House 
to Work- 
shop, garage, inter- 
office, etc. Works off 
any small battery, 
P. & P. 4'6. 



VALVES. 9d. casta. 1,000'. available. Bend tar 

list. 

CONDEHSEBS. 100—10/-. Krw. Aaaorltnl 

cja :.ioi> iia ftnd l>Fs. 9' * P- Br* 

V/CONTBOL8. ->»-10/-. A itttcttaa of iyo«* 

and eiie*. P. & P. '2,'tt. 



Phone 
ILrord 

6001/2/3 



DUKE&CO.(LONDON) LTD. 

621/3 Romford Road, Manor Park. E.I2 
Liverpool St. — Manor Pk. — 10 mins. 



Stamp 

For Free 
List 



VALVES SAME DAY SERVICE 

• armeW w Bam* asf ucw i tccteh I eniDiiiTCCn I 



NEW ! TESTED ! GUARANTEED ! 



RFTK 'tis. Ida. IT1, 354, 3Y4. DAF91. DrJI, DKal, mm, I>L94i Set 
*"* ' ° o* 4 fur 16/-. DAMS. DF9U, UK9U, OJM: * for 83/6. 



1A7GT 


7/8 rtVUO 3/9 


CMX'SO 


cm BfOJM 


6ft 


rcFsa 6/9 


I 1 it 


6/6'IV'fUT 6/8DK;« 


SI- K'L.^J 


7/- ; PCPB4 S/- 


iH;>i;T 


B/BflXJ S/I-DFJU 


a/fl El ajw 


9/. I > ( J'-t. g(- 


1 SftGT 


BV-'flXnGT 5/8:l>F9ti 


67- EFS9 


8/9 Pi:Frt06 14/- 


IM 


4/9,7 BT 8/-.DH7d 


3/6 EF41 


6/6 POW9 8/B 


|fj 


3/9 706 7/9;PHT7 


3/8 EF49 


4/8 PrlJss B/- 


1T4 


aft 


706 7/6 DKJ2 


8/- EPS0 


4/8 . POLS4 7/6 


IC8 


an 


7H7 6/9IDKS1 


4/8 FF8S 


*/- ! PCI.84 8/8 


HAS 


787 18/9 DK.9-2 


819 lii'SiJ 


6/8 


PE.N4UD 


KM 


4 no 


7Y4 S/-IDK98 
IOCS 18/8. OLSS 
lllA'Pfl 4/8 1 DL35 


6/6 F.F89 


4/1 


19/B 


tat 


4 fit 


7/ 3 EF91 


m 


PEN A J 8/8 


3V4 


BM 


6/9 EF9i 


m 


PEKB4 17/6 


BtTeG 


4/6 


«AT7 8ifDI,M 


97- £1.3^ 


LkVI 


PBK883 9/fl 


DYSGT 


5/- l'JAl,"7 4/9 


DL93 


4/9 EI.41 


7/6 


PL36 B/6 


OEM 


7/- 


12AX7 4/9 


OL94 


fl/S EL84 


4/9 


PL61 7/- 


(1AI.5 


ft*. 


12K7UT i/3 

li&aot a/a 


DLW 


8/- EMS4 


Tfll 


PIM 6/1 


8AQ13 


«/- 


KABO80I/3 EMSO 


6/9 


PLSa B/- 


GATU 


a/o 


l'JG7GT 4/8 

itiiw Hi 


EAF42 


8/- KM-i 


7/9 


PLS4 6/9 


tJBAB 


ft* 


KB41 


4/- EM 84 


7/1 


P.K4 9/- 
PX'Jfi 7/9 


<lHF.it 


20P4 18/8 


EB91 


2/-IEM87 


8/- 


'. !!■ i'ii; 19/6 


SOPS 14/9 


EBC3S 


5/- EVjl 


6/- 


PY31 5/9 


HBHd 


6/8 


45UIGT 4/9 


EBC41 


7/8 EV84 


7/- 


PYS2 9/- 


lIBJD 


aSU4GT 30/6 


KBCS1 


6/9 snraa 


6/8 


PY33 97- 


6F1 


»H 


301.15 8/B 


EBF80 


B/-EZ40 


EM 


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8F18- 


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3UFL1 8/- 


EBF8S 


7/8 EZ41 


7/6 


FYS1 5/B 


sru 


»/- 


30P1.13 9/- 


EBFS9 


8/-' EZS0 


4/-IPT8-2 4/9 


6F15 


IM 


80PL14ia/8iFBl^l 


8/S 


EZ31 


4/8iPTSS 6/9 


tSKTO 


Irt 


38A3 14/- BCC40 


7« 


KT32 


5/-IPVS8 7f9 


6K7GT 


«. 


aSUiOT 8/3>ECC81 


3,'S 


KTtifj 


12/S!£1. 15/- 


asm 


«M 


S5Z4GT4/1DECGS-2 


^ 


K-TW'J: 


4/9 TDD4 7/9 


I.K-.GT 


7/9 


8.1EU 8/6 ECT83 


UCU 


8/- TH21C 9/9 


am 


5/8 AK 31 8/8 BOOM 


u/a 


UX40 


8/8 TH'238 6/9 


•ua 


7/8 B.lt> 4/61ECVS5 


Ul 


S18 


4/10 DU 4« 


■Ma 


B/8 IX_'H38 L8/3:ECF80 


6/3 


PC9B 


B/- mi 8/1 


gars 


4/9 01.33 1/8 ECF82 


6/3 FC97 


7/6IUS6 10/- 


6Q7CT 


7/9 c¥i 18/e.ECFsa 


10/9 PCOS4 


5/6 D47 8/6 


«p,;gt 


9/9 DAC3S 8/8-ECH35 


8/-PCC85 


9/9 U50 8/- 


6SL7GT 5/6 DAF91 3/8 BCH42 


9/3iPCC89 


e/-mwi 4/a 


88.S7GT 3/9 


DAF9S e/- 


ECHS1 


6/- 


FCFSO 


6!9 


ti76 S/B 



1.19L 
L'flSl 

I 239 
L291 

f" -if! I 

I 4090 

'Alii 8 
LAF4 
TIBlMl 
I. BC81 

vni-Hti 

awfsa 

BOM 

icr'84 

l'(X!65 
UCFW 
LCU42 
UCHB1 
! 0149 

rcLS3 

TO 1 

crwa 

1/FS9 

L L41 
IL44 

ri>w 

UI.84 

VC7 

cua 

IY21 

IY41 
C¥8e 
7P41 
W76 

W77 
W729 

xsiJt 

X109 



a/6 
a/6 
11/9 
•/- 

16/9 

1/6 

"5/9 

B/S 
7/8 
91- 
6/9 

r. 
6/9 

8/| 
7/8 
B/6 

m 

8/3 
7/8 
4/9 
8/3 
7/- 

16/- 
8/8 
6/3 
9/8 

10/9 
7/9 

4/e 

6/- 
4/9 
8/8 

m 

16/6 
19/6 
17/8 



Readers Radio 

24 COLBERG PUCE, STAMFORD HILL, LONDON N.I 6 
STA. 4537 

Port W. fitirmiTttzl.ru. Anv Far«i liuijis.lsaalrnt Damage in Tnuelt 6<L erti-i 
Aay 0.0. D. Parcel 4/3 eitrs. 



August, 1964 



PRACTICAL WIRELESS 



301 





THE HIGHWAYMAN' 

OUR QUALITY CAR RADIO 

TO BUILD YOURSELF AT 

A NEW LOW PRICE 

Look at these features: 
■*• Attractive styling. ■*■ Push- 
pull output. # Throe latest 
Mullard transistors plus valves types EBF&J and ECH83. ■* No 
Buzz, high output and sensitivity. • Printed cirouit Uatest 
tvpe). 7 x 4in. fcisrb riux p.m. speaker and baffle. ■*■ Medium an<J 
Long- Waves. * Pusji button for fingertip control. •*■ Extremely low 
battery consumption rless than ; .-amp). * Easy to fit any make car 
(Positive earth only). -*- 12-volt operation, -k Compact size, meas- 
ures only 7 x 7 x 2in, deep, * Easy assembly, supplied with dial and 
drive already mounted. £7 1 Q ft Plus 5/- P. & P- 

SpecialinclusiveprlceofONLY * I . I 3 ■« 
All parts available separately. Individually priced parts list and 
comprehensive instruction booklet 3/6 post free. (Deducted Irom 
cost if complete parcel purchased later). 

Optional extras. 3 section chromium plated weatherproof 
telescopic aerials type l 17744". 1976: type i, a 743". 29/8, both 
plus P. & P. 2/6 if purchased separately. 



MARTIN Fully Transistorised AUDIO KITS 

These ingeniously designed sub-assembled kits enable yoa to build 
a transistorised Hi-Fi system by simply linking together your 
choice of units. No technical knowledge or special tools are needed 
to build with complete suc- 
cess. All units are supplied 
on printed circuit boards 
ready to mount and connect. 
Latest type transistors used 
in conjunction with the 
specially developed circuits 
give you superb reproduction 
or battery operation or can 
be used on A.C. mains with 
Martin power supply unit. 

Following Audiokits available: — 

I* nit I,— 5-Stage Matching Input Selector Unit, 47/6. 

Unit 2.— Fre-Ampliiler with Master Volume Control, 37/6. 

Unit 3.— 3-Channel Mixer, 79/6. (Plug-in matching adaptors fop 

above. 8/8 each.) 
Unit 4.— Combined Fre-Amplifler and Tone Control Unit, 82/6. 
Unit 5,-10 watt Main Amp (3 ohm o/p imp. only at present). £5.12.6* 
Unit 6.— Power Supply Unit. £2.12.6. 

P. & P. extra on above items. Full range of attractive perspes 
escutcheons available. Send S.A.E. for fully descriptive literature. 




THE WORLD AT YOUR FINGERTIPS!! 



THE HE-30 4-BAND COMMUNICATION RECEIVER 

One of the finest, general 
coverage bandspread Recei- 
vers available at this price. 
Covering 550Kc/s— HJOOKc/s. 
4.8MC/S— 14.5Mc/s, 1.6M.C/S— 
4.8MC/S, 10.5MC/S— 30MC/S. 
Illuminated slide rule djal. 
calibrated every 5Kc;s on 80 
and 40 metres. Edgewise 
S-meter. 0-100 logging scale, 
coverage from 0.55— 30Mc/s. 
B valve plus Re el Her super- 
het circuits. RF stage with 
an Aerial Trimmer. 2 IF Stages, B.F.O, control Q-muliipller. 
Controls: Function Switch, Audio Gain. Selectivity iQ-muItlpllen 
Frequency <BFO). Band Selector. IF Gain. Trimmer, AVC-MVC 
Switch. Anl Switch. Main Tuning. Bandspread Tuning and Head- 
phone Jack, Selectivity— SOdB at lOKc/s. 0.8Kc/s at 6dB (with Q- 
muitlplier) IF-45oKc/s. External PM Speaker read., 4 or 8 Ohms 
Impedance. Output l.a watts, a modern Miniature B7G Base Valves 
and 5Y3 Rectifier. Size 15 x 10 x Tiin. Grey crackle finish. 220/240 
volt A.C. mains. 50-60 cycle operation. Full instructions and 
circuit diagram supplied. Send S.A.E. 
for leaflet. AQ fine Carriage 




I-'HICS 



Paid 



THE HE -40 4-BAND COMMUNICATION RECEIVER 

Completely built a nd ready 
to eo. High se nsitivity 
Superhet receiver covering 
650KC/S— 1,600 Kc/S, 1.6 Mc/s 
—4.4 Mcli, 4.4 Mc/s— 11 Mc/s 
11 Me/s— 30 Mc/s, Electrical 
bandspread tuning. Slide 
rule type tuning dial. Inter- 
nal ferrlte rod aerial lor me- 
dium waveband reception 
and 1 59tn. 10 section chro- 
mium plated telescopic whip aerial for the shore wave bands 
Sockets for optional outdoor aerial, internal high flux monitor 
loudspeaker. Latest modern miniature B7G base valves. Head- 
phone socket fmav also be used for external loudspeaker). ANI* 
BFO. built-in "8" meter. 220/240 volt A.C. mains, 50-80 cycl* 
operation. Handsomely styled cabinet with grey cracWe finish an* 
handsome front panel, with chrome and satin chrome fittings. 
Measures 13Un. x Sjln. x 5jin. (nigh) and weighs only lit lbs. A 
comprehensive instruction manual is supplied. An ideal receiver 
Tor the radio amateur and short wave listeners of all ages. 
Send S.A.E. lor leaflet. 




PRICE 



£24.15.0 °%l\T 




THE NEW HE-80 COMMUNICATION RECEIVER 

The HE-80 has out- 
standing sensitivity 
0-100 logging scale for 
.instant re-set. built-in 
"S" meter special rec- 
ording Jack. remote 
Control Socket allowing 
simultaneous control 
with transmitter, lOOK/c 
crystal oscillator circuit 
providing accurate har- 
monic signals of either 
4 or 8 ohms impedance. 
Two headphone sockets, 
one high, one low. 
TECHNICAL SPECIFICATIONS. 

Frequency Coverage: Band 1 540— 1505Kc: Band 2 1.6— 4,8Kc; 
Band 3 4.8— H.SMc : Band 4 10.5— SDMc ; Band 5 144— 146Mc/s. Band 
Spread (Ham Band directly read): 80 Metre Band; 40 Metre Band: 
20 Metre Band: 1? Metre Band; 10 Metre Band. Sensitivity: l micro- 
volt for lOdB signal to noise ratio. Selectivity: Normal lOKc at 
— 75dB, 1.25 at— SdB. With Q-multi: variable to 700 C.p.s. at 6dB. 
Operation: AM. SSB. Cff and FM, AM diode detector. SSB/CW 
product detector fBFO), FM gated beam detector. Power Source: 
240 volts 50/60 Cycles A.C. Power Consumption: 60 watts. Audio 
Output: 1.5 watts, 8 or 500 ohms impedance. Auxiliary Circuit: 
Electrical Bandspread. Q-Multiplier, ANL. AVC-MVC. BFO. lOOKc 
crystal calibrator. Valve Line-up: 4 — 6AQ8.6BL8.3 — 6BA6. 2— 6BE6, 
6AL5, 6AQ5, OA2, 6CA4. Dimensions: ITin. wide. 6iin, high, lOln, 
deep. 



price 59 Gns. €& £ST 




"STARFLITE TRANSMITTER" 

Designed to meet the needs 
of most amateurs the Star- 
flite has single-knob band- 
switching. Front panel 
switch to select any of live 
crystal positions with pro- 
vision for an external VFO. 
Controlled carrier modulator 
permits almost 100% of the 
CW input to be used on AM 
peaks. Grid-block keying 
provides chirp-free operation. 
A full wave silicon diode 
power supply effects extre- 
mely low output ripple for, 
cleaner CW transmission, electron-coupled Pierce Oscillator, 
capacitance bridge neutralization of the final and a three-staga 
lowpass filter. An illuminated edgrewise D'Arsonval panel meter. 
PI -network output provides the correct impedance match between 
the plate circuit and any 50-72 ohm co-axial feeder. Easy to follow 
point-to-point Instructions supplied with each set of components. 
When constructed the Unit is housed in a heavy gauge steel Cabinet 
finished in grey crackle. 

SPECIFICATIONS: Power Inout— 20 watts peak; Operation: 
C.W., AM Phone— crystals or VFO Control; Band coverage: 80-10 
metres; Coupling: Pi-network: Valve Line-up: 6146. (2) 6CL6, 
12AX7, 6DE7. Low Pass Filter. Size 13iin. wide x 12in. deep (inc. 
knobs) x 6}ln. high (inc. rubber feet). Weight 23 lbs. Power Require- 
ments, KJO/240 v. 50-60 CFS, 225 watts. 

MAY BE BUILT FOR 35 GflS. 



Carriage & Insurance 15/- 



SEE FOLLOWING PAGES FOR ADDRESSES AND OTHER ITEMS 



302 



PRACTICAL WIRELESS 



August, I9d> 



frpSH 

r J ELectronu 




ELectr&tticd Centred throughout Qre&G BtvGcusl* 






£10.0.0 
£13.13.0 

£1.6.0 extra. 



MULLARD 2-VALVE PREAMPLIFIER TONE 
CONTROL UNIT 

Employing two BF36 valves and 
deafened to operate with the Milliard 
AMPLIFIERS but also perfectly suit- 
able for otter makes with input up 
to250m/V. 

■*■ Equalisation for the latest R.I. A. A. 
characteristics. * Inputs lor Crystal Pickups and variable reluctance 
magnetic types, -jt Input (a) Direct from High imp. Tape Head, (b) 
From a Tape Amplifier or Pre- Amplifier. * Sensitive Microphone 
Channel. *■ Wide range BASS and TREBLE Controls. 
KIT OF <>fi ft fl ASSEMBLED CO -t ft ft (Carr. & 

PARTS SO.O.U AND TESTED »5>« IU»*» Ills. 5/- 1. 

Instruction book and detailed price list (free -with kits) available separately 
at a/- Post Free. 

MULLARD 3- VALVE PRE-AMPL1F1ER TONE CONTROL 
UNIT 

Designed mainly Tor Mullard Range of 
Amplifiers, also suitable for any Amplifiers 
requiring input up to 230m V. incorporates 5 
Input Channels, Including for Tape and Mag- 
netic Pickups. Separate Bass and Treble 
controls. High pass filter 30 to ISO o/s. low 
pass filter 5-9 Kc/s. Totally enclosed in case 
Size Hi x <Si x ii. Jp1 ft ft A COarr. & ASSEMBLED jp-f O -JO ft 
KIT OF PARTS * ' V.V.V m3 , 5/.). & TESTED * ■ "*■ ■ "*- U 
Instruction book and detailed price list (.free 'with kit) available separately 
at 3/6 Post Free. 

MULLARD "5-iQ" MAIN AMPLIFIER 

For use with MULtjAJtD 2 or 3 valve pre- 
amplifiers with which an undlstorted 
power output of up to 10 watts is obtained. 
SPECIFIED COMPONENTS and MUL- 
LARD VALVES including PARTRIDGE 
MAINS TRANSFORMER and choice of 
PARMEKO or PARTRIDGE Output 
Transformer. 
COMPLETE KIT 
(Parroeko Output Trans,) 
ASSEMBLED AND 

{Carr. & Ins. 6/6). TESTED 

ABOVE IncorporatiiiE PARTRIDGE OUTPUT TRANS. _. 

Instruction bock and detailed price list (free with kit) available separately 

at 31- Post Free, 

COMBINED PRICE REDUCTION 
MUIXARD 5-10 Main amplifier and 2 valve Pre-Amp. Kit £15.15.0. 
C. ft I. B/6. Built and tested. £81.10.0- C.4I. 10/-. 

ML'IXAKI) 5-10 Main Amplifier and 3 valve Pre-Amp. Kit £19.10.0. 
C. ft 1. 8/6. Built and tested, £25.10.0. C. ft 1. 10/-. With Patrtridge Trans- 
former £1-6.0 extra. 

THE MULLARD S-IORC AMPLIFIER 

The popular complete "5-10" Incorpora- 
ting Passive Control Unit providing up to 
10 watts high Quality reproduction with 
input of SOOmV. Specified components 
and new MULLARD VALVES. Includes 
PARTRIDGE MAINS TRANSFORMERS 
and choice of PARMEKO or PARTR1DGK 
Output Transformers. Surplus power 
available for Tuner 
COMPLETE £-12.0.0 
ASSEMBLED fie ft ft (Carr. ft Willi PARTRIDGE OUT- 

AND TESTED *■ W.U.U Ins. 7/6). PUT TRANS. £1.8.0. ex. 

Instruction book and detailed price list t.free with kit) available separately 
at 21- Post Free, 

THE MULLARD 3-3RC 

A HIGH QUALITY AMPLIFIER DEVEL- 
OPED FROM THE VERY POPULAR 
S- WATT MULLARD "3-3" DESIGN. 

||gtf KIT OF PARTS £8.8.0 
W& ASSEMBLED *1 1 1 ft ft (Carr. ft 
Hf AND TESTED * ■ ■ • ■ "■" Ins. 8/6). 
pt» Complete to the MULLARD specification 
including PARMEKO OUTPUT TRANS- 
FORMER. Switched Inputs far 78 and 

L.F. records plus a Radio position. Extra power to drive a Radio Tuning 

Unit is also available. Please state L.S. impedance. 

Instruction book and detailed price list (free with kit) available separately 

a: -21- Post Free. 

TAPE PRE-AMPLIFIER MULLARD Type 

Suitable for most i track. Mono Tape 
Decks. Incorporates Ferrox-cube Push- 
pull Oscillator, Treble Inductor and 3-sp. 
Equalisation. Includes separate Power 

rant 






Kr t op £1d n A (Carr. ft 
PARTS »I«MMJ Ins. 7/8). 



£19.10.0 



_s. 7/6), ASSEMBLED 

Instruction book and detailed price list (.free wtth kit) at«i table separately 
at 3(6 Post Free. 



SEE PRECEDING PAGE FOR 
OTHER STERN-CLYNE PRODUCTS 




£6.0.0 



THE "MONO-GRAM" 

A email Amplifier of genuine high 
quality performance. Incorpor- 
ates MULLARD ECL8G Valve, 
separate BASS and TREBLE 
controls. PARTRIDGE output™; 
Transformer producing up to 3?* 
watt:: undlstorted output. (Carr. \ 
ft Ins. 3/6). t 

KIT OF pM I ft ft (Carr. ft 
PARTS "*" fcu Ins. 3/6). ASSEMBLED 

Instruction book and detailed price list ifree with kit) available 
separately at 2/6 Post Free, 

Perfectly suited for Portable Installa- 
tions for which purpose we offer PORT- 
ABLE CASE (£3.10,0), the AMPLIFIER 
(Kit ¥4.10.0) and 8* x 5- £ft ft ft 
SPEAKER ((1,0.0), All for.. *O.U.w 
Alternatively with 

ASSEMBLED AMPLIFIER rift ft ft 
Can-, ft Ins. 5/-). * ■ v.U.W j 

The Case quoted above will accommo- 
date some 4-speed Single Record Units. 
A larger model is available for extra 10/-. 
With this Equipment a COMPLETE 
PORTABLE RECORD C-t A ft ft 

PLAYER can be built for *I**.U.U 



MODEL CR3/S 
TAPE RECORDER 

MODEL CR3/S Incorporates 

the HF/TR3 Mk. n Tape 

Amplifier (described below) 

and the Collaro "Studio" 

Twin-Track 3-speed Deck 

operating at llin., 31in. and 

7s in. speeds. Complete 

with microphones aaC 

1.200ft, tape. 

KIT OF 

PARTS 

ASSEMBLED 

AND TESTED 

(Carr. ft Ins. 





£33.8.0 
£43.0.0 



jiifffifri 



'**--J' :V « : ' :: 

**£* s a , 




STEREO TAPE 
PRE-AMPLIFIED 
MODEL STJM. For use 

with current TRUVOX. 
HkENELL or COLLARO 
"STUDIO" } and k track 
Stereo Decks. Incorpor- 
ates Ferrox-cube Oscillator, 4-speed Equalisation Signal Lever 
Meter and separate Gain Control. Includes separate Power 
Unit. KIT OF Cnn ft a (Carr. ft fna ft ft 

PARTS **A.U.U in„. e/6 , ASSEMBLED **O.U.U 
instruction t>6ok and drtalted price list (free with kit) available 
separately at 5/- Post Free. 

MULLARD TAPE AMPLIFIER 
MODEL ill ■■<'] '113/ VI K. 11 

Based on Mullard' s Type "A" 
design and suitable lor most * 
tract: Mono Tape Decks. Incor- 
porates Ferrax-cube Treble in- 
ductor, Gilson Output Transfor- 
mer, and 3-speed Equalisation. 
Includes separate Power Unit, 
using PARTRIDGE Mains Transformer. 
KITOF 4? 1 4 1 1 ft (Carr. ft 

PARTS * I «J. I J.U InSi llei ASSEMBLED 

Instruction book and detailed price list (free with kit) auatUtbte 
separately at y- Post Free. 




£19.0.0 



COMBINATION TAPE UNITS 

All our Tape Doits can be supplied specially matched to any Tape Deck such as 
Collaro Breneti Mk.5 Series if. also the Weaiite. Specimen price* 11 inflow 

Kit Aucmbles 

SCT-l Pre-amp with Collaro Studio Tap* Dec*.,.... £38. 0.0 its. 0.0 
AHieuiUleil with track twitch fitted, £44,2.0. 
STP-1 with Brenell ilk. S aeries 11 with Track Switch 

rttteii ISR. 4.0 

8TP-1 with Breueil Mk.S Series U, J Track Deck 474,16.0 

Type "C" Pre-«nip with Collaro Studio Tape Deck ££4,10.0 ISO. 0.0 

Ajw^mbled with Ji.-i.-k wired and matched. £32,2,0, 

Type "0" Pre-aiup with Brenell Mk.3 Series U Deck.. £48.11.0 £53. 1.0 

Assembled with deck wired and matched. £55.3.0, 

RT TR3 nit h Collaro Studio Tape DeeS £24. 8.0 ££9.10.0 

Amembled with deck wired and matched, £31,12,0, 

HF.TR3 with Brenell Stk.O Series U Dett £40, 4,0 15L.U.0 

Ajaetobieil with deck wired and matched, £53,13.0. 

Carr. « [na. 15/- on above units. Bead d.A.E. for camprehensJTe price lilt. 



SEND FOR CURRENT PRICE LIST OF ALL LEAO- 
INC RECORDING TAPES AND ACCESSORIES 



August, 1964 



PRACTICAL WIRELESS 



303 



r J ELectronu 




ELectrofUed Centred throughout great Britauu 



THE TUDOR STEREO HI-FI SYSTEM 




/ 



feSsftfe-s 



iif 




Comprising a Self Powered AM/FM Tuner. Stereo Pre-ampHfler, 12 watt 
per channel Stereo Power Amplifier. The Tuner and Pre-ampHfler are 
housed Jn matching black crackle finish metal cabinets for shelf mount- 
ing, with stiver metal dials and matching knobs. Specifications: Tuner: 
Outstanding quality providing full VHP/ 
F.M Ion? and medium waveband coverage, 
frequency range F.M 87 5-108.5 Mc/s. AM/MW 
522-1630 KWs. LW 145-270 Kc/s. 100m V Output 
mains supply 105/240 A.C. Valve line-up: 
ECC35. ECH81, EBF89, EB91. EM84. 

tECC-33. Multiplex outlet provided. Pre- 
a A j umtill li cr— Designed for use with Tudor 
« Stereo Power Amplifier with Inputs for most 
types of Pickups, direct play from Tape- 
Heads and ample sensitivity for either Crys- 
tal or Moving Coil Microphone. Distortion 
0,1 °„. tape outputs lOOmV from 90K. ohm 
source inputs—Microphone 5 mV. Tape 
5.3 mV. R.I.A.A. 4.3 mV flat 250 m V.Tuner 
100 raV. Valve line-up: 2— EF86. 4— ECC83. Poww Amplifier.— 14 
watts per channel, sensitivity 1 volt r.m.s. for 14 watts output, ire- 
quency response ^O.adB 20 e/:, — 20Ko/s. Speaker Impedance 4. 8. or 16 
ohms, surplus power available for Tane Pre-Amn. mains supply 105/240 
v. A.C. Valve line-up; 2— ECC33, 4— EL84. 1^GZ34. 

DUE TO PRODUCTION STREAMLINING WE ARE 

PLEASED TO ANNOUNCE REDUCTIONS IN PRICE! 

* J.L.10 POWER AMPLIFIER 

Incorporates the latest tr'.ode-pen- 
tode ECL8G valves In push-pull, 
PARTRIDGE ultra linear output 
transformer. PARTHIDOE mains 
transformer and smoothing choke. 
10 watts power output, surplus 
power available for tuner. Output 
Impedance 'j — 7,5—15 ohms. 

£in ft n c. & i. 

KIT OF PARTS *IU.U.U -,$ 

READY BUILT ** 3.1 3.0 
* DOUBLE FEATURE PRE-AMPLIFIER 

Inputs for microphone, crystal or 
magnetic pickups, tuner ,.ni;. 
and in addition offers full facilities 
for tape recording and high fidelity 
replay. This unique feature means 
that should you wish to Include 
tape fn your hl-ft system at a later 
date all that Is required is a suitable 
tape deck. Push-button switching 
for 3 tape sneeds equalised. Tape 
erase Bias Oscillator circuit Incorporating ferrox-cube transformer. 
Function switch, separate ba-=e. treble and volume control*, level 
control and latest EM87 ma?it- eye level indicator. The Die-amulilier 
is totally enclosed in a silver hammer finish steel case, and an attrae- 
tlver perspex front Panel completes the presentation. 
KIT OF PARTS £1 3.1 3.0 READY BUILT £1 9.1 9.0 C & 1. »- 

PRICES : If both above units are purchased coirethei' : 
KIT OF PART--; £23.13.0 READY BUILT £32.0.0 





C. <fct. 

10/-. 



ACOS MONAURAL STETHOSCOPE HEADSETS 

Suitable ft*r Tap* Recorders, or monitoring tape recorders, 100 ohm 
Impedance magnetic. Complete with lead. m ^ n „„.„,, 12/6 & 



(Originally 21/-). 



OUR PRICK 



I/-. 




SEND STAMP FOR COPY OF OUR INTERESTING LITTLE 
BOOKLET "What h High Fidelity?" 

CHASSIS BARGAIN 

A 6 valve Superhet Radiogram 
Chassis of outstanding quality 
Covering MW 200/550 Metres, 
LW 1200-2000 Metres. VHP 87- 
lOOMc/s. 

Incorporating internal Ferrite 
Rod Aerial and the famous 
Corler Tuning Heart for VHP, 
Pick-up input suitable for most modern Record Players. Power 
output 4 watts, valve Una up E180. EABC80, EF86. ECHT1. 
EL84. ECC85. Volume On/Off and Tone Control, attractive 
black Tunlne Dial size 15- x 6- with gold lettering and con- 
trasting cream and gold knobs. A.C. 200(250 v. Size 15 x 7: x t.i ", 

PRICK 1 6 GnS. Or £39.0 deposit {plus P. & PJ and 9 
monthly payments of ae/8. 

HI-FI STEREO HEADPHONES 

For the connoisseur who requires pet^ 
fection. Each Karphone consists of a 
2i" Dynamic Loudspeaker with a full 
irequency range, fitted with foam rub- 
ber Ear Pads for added comfort to 
keep out noise and to maintain an 
excellent bass response. The resis- 
tance Junction box with change-over 
switch provides simple transfer from 
Phones to Speaker: Specifications; 
Frequency Ran ge-25- 15. 000 c. p. s. Input 
Impedance— 16 ohms. Power rating— 
1 watt. Weight— 18 ozs. 

PRICE 5 GnS. P. & P. 2/8. 
(Junction box 15/- ex.) 

OUTSTANDING PRICE REDUCTION 

_ THE B, & O. 

rfT/M PICKUP 
COMPLETE 
WITH SP 11 
- J ?~~N fc STEP.EODYNB 

I - ^W MAGNETIC 

^1*. CARTRIDGE 
A Transcription 
-*•« Pickup of out- 
standing quality 
employing a spe- 
cially designed 
counter-balanced and unique weight adjustment. 
Specifications: Length lOlin. from tip oi Cartridge. Height 2iin, 
Steieo/Muno Cartridge. 

Frequency Response: -2.Sd8 from SOc.p.s. to 15 K.C. 
Output Voltage: 7roV per channel at 5 cm/sec, at 1000 eps. 
Separation: 20dB minimum. 
DC Resistance: 12iu ohrus. 
inductance; 200mH. 

Recommended Tracking Force: 2 to 4 grams. 
Compliance; S x 13-H6 cm/dyne in all directions, 
Stylus: Diamond, radius of curvature: 7th. 
Recommended Load: 47000 ohms, qi Arte 
j PRICE a T mi». 







-„-" 



Plus W P- & P. 



NEWS FLASH ! t 

YET ANOTHER NEW ELECTRONICS CENTRE 

OPENING SHOftTLV AT 

52, LORD STREET, LIVERPOOL 



WEST END: 
(Premier Radio) 
(Premier Radio) 

CITY: 

NORTH LONDON: 

SOUTH LONDON: 

CROYDON: 

BRISTOL: 

MANCHESTER: 



1 8 Tottenham Court Road, W.I. 

23 Tottenham Court Road, W.I. 

309 Edgware Road, W.2. 

1 09 Fleet Street, E.C.4. 

1 62 Holloway Road, N.7. 

9 Camberwell Church Street, S.E.5, 

12 Suffolk House, George Street. 

26 Merchant Street, Bristol I. 

20 22 Withy Grove, Manchester 4. 



MUSeum 5929 0095 Half-day Sat 
MUSeum 3451,2 Half-day Thurs 
PADdtngton 6963 
FLEet St, 5812 3 



NORth 7941 
RODney 2875 
MUNicipal 3250 
Bristol 20261 



Half-day Thurs 
Half-day Sat. 
Half-day Thurs 
Half-day Thurs 
Half-day Wed 
Half-day Wed 



Mail Orders and enquiries to Dept. P.W. 3 5 Eden 



BLAck Friars 5379 Open 6 days a week 
Grove, Holloway London, N.7. 



304 



PRACTICAL WIRELESS 




BENTLEY ACOUSTIC CORPORATION LTD. 

Suppliers to H.M. Government. 38 CHALCOT ROAD. LONDON, N.W.I T C ie P Son«: primrose 9two 

NEAREST UNDERGROUND: CHALK FARM. ALL UOODj lISIeJ BELOW ACTUALLY IN STOCK 

ALL GOODS ARE NEW, BEST OUAUTY BRANDS ONLY, AND SUB JECT TO MAKERS' FULL G UARANTEE. PLEASE 
NOTE THAT WE DO NOT SELL ITEMS FROM FAULTY EQUIPMENT NOR MANUFACTURERS' SECONDS & 
REJECTS, WHICH ARE OFTEN DESCRIBED AS "NEW AND TESTED" BUT HAVE A SHORT AND UNRELIABLE LIFE 



OA2 


4/6 [ OBWti 


6/9 BX6 4/6 


■jui'o is/a 


Acm.imsi- 


EABC'i 5/6 i EL37 


i£/3 ktjui 6/6 u^i.M.'iae/ei rso 4/6 


1 AF1SS 10,6 


OB9 


e/- 


6BW7 


S/- 


GY'ii; 6rf- 


'JSA'iO 7/6 




F.AC91 3/8 


II. 11 


7/3 


LH3 31- 


H1-- 5/9 


Vfl 4/B 


, \II2G 10/- 


O'SAGT 


4/3 


8BX8 


3/9 


0Z4 51- 


25L8 4/9 




KAK42 7/6 


F.M'2 


7/6 


Lsies 6/- 


Rl-1 £9/- 


L'78 4/B 


Al'127 9(6 


lA;i 
IAS 


2/6 
5/- 


BOB 


£/3 
4/- 


7A7 12/6 
-liii 12/0 


■2SLMOT16/2 
■2BYS 7/f 


(71 17/- 


BtHH I/- 

EB41 4/8 


El^il 

ilia 


8/3 
C/C 


1. Villi* 7/B 
LSS19 8/6 


KIT 17/8 


L-78 s/e 

-i lo/u 


1 BYZ13 11,6 

ana s/e 


B - BM 


]A7(JT 


7/B 


■ ii'.i 


8/-I7B7 7/- 


■2SV5G 7/fi 


vi -'■ 82/6 


mini s/3 


i:l^i 


4/6 


l./l:ll» 5/6 


Rio s/e 


L101 19/ti 


:<iini 6,8 


K'l 


4/- 


BOB 


3/- 7C3 7/8 


ass4u e/e 




Kill .. 20/0 


KLJ43 


7/8 | LJ«HB 5/6 


k.v> e,- 


I.HI7 17/6 


HUM 10,'- 


1C2 


8/8 




10/9 


7<u 6/9 


■IS7A 7/8 


IB/- 


bl HI 31 8/8 


RIM 


7/3 I.I': 9/6 


l:i-l 24(1 A 


i.'iyi B/e 


2 8(8 


1L-3 


a/a 


0CI0 


7/8 


vi).-; 15/- 


•is /WOT 8/- 


ACTH1 16/- 


EH* '4! 0/6 


Ki.rn 


2/6 MK4I 15/2 


54/- 
HK34 7/8 


i tei 6- 


GET 108 7/- 


vta 


6/3 


8018 


6/- 


71)3 16/- 


J7SIJ 23/3 


AfTP 13/- 


KBC81 5/9 


axas 


6/6 


\J 191 12/6 


0881 S/B 


GET1041O/- 


H'j 


10,'G 


OCIT 


12/6 


TiJ'i 14/8 


■•-■i7 e/9 


AC S l'l 12/. 


ElH-!tli 3/8 


Butse 


27/- 


HIM 3/8 


siae 2£/6 


U'iS'J 12/8 


<;KT10H17/6 


IDS 


6/0 


'IUDUG 


18/- 


7D9 1B/- 


:Hm_l 5/8 


ACVPS 2U/S 


BBOB1 in 


SL890 


18/4 


Vilj;>4 8/- 


si'4B ie/B 


r :<>l U/3 


GET1U18:- 


IDS 


9/8 




6/- 


7B7 6/9 


3IK.-1S 9/- 


A'l'1'4 2/3 


BTBP86 5/6 


ELKM 


18/6 


MHl.i)iil£/G 


BF1SO 12/6 


L'3-29 W- 


oBTita e/e 


1KI 


s/b 


•H7W4 


24/- 


7R7 12/6 


S0C1S 10/6 


A/ 1 6/6 


BUBP8S 7/3 


lil.LSO 


20/5 


HM 5/9 


8DP41 2/- 


U339 8/8 


0ET114 6/6 


] l-'J 


£/S 


ODl 


1/8 


7s*7 14/6 


30FS 6« 


A/.31 6/8 


K li l-'-'.i B/3 


i:>!4 


17/9 


MS4H 20/5 


- 1* i a 12//. 


C4M e/e 


U ET !* 7-210;- 


1F3 


2/3 




9/6 


7Y4 6/- 


■WU 9/3 


AZ41 6/6 


KBlatl 3/- 


BU84 


u/e 


M3P4 12/- 


SlMl -/- 


L'4IH 0/- 


iiin>7a 8/3 


1KLU 


6/9 


6D6 


8/- 


SDi 8/8 


SOLI 5/8 


BM 4/3 


BCM 4/3 


BM83 


12/- 


MUia/14 4/6 


SU38 B7/8 


UttOI 10/3 


GET«74 9/8 


1FD9 


3/8 


i; k.-i 


9/6 


sBWii 0/8 


38L15 9/3 


B319 8/6 


MM i2,'i; 


EMil 


13'G 




-f.;i s/b 


149-20 6/8 


. 3,- 


Hi.'. 


«/- 
7/D 


UK l 


6/8 


li Da 8/- 


301*4 IB/8 


i- 1. •>■:, 10/6 


EC54 8'- 


F.Msn 


6/1 


S:-i7 23/3 


T4i e/- 


VilKiOll/B 


■ 10,- 


1H901 


898 


6/3 


9U7 7/8 


SOFIS 7/6 


n 12/6 


E<:to 4/9 


BMS1 


7/- 


in 2u/- 


; UH'2 12/8 


VMS4B 1SI- 


8/8 


1L4 


in 


Hh'itO 


S/B 


IOC I 8/S 


:W1P16 0/- 


■ 10 12/8 




BH84 


8/9 


stim 20/£ 


mill s/- 


VP-2 S/6 


) U/6 


1LAS 


ta/io 




V* 


MOB 12/3 


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■ CH3S 12/6 


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BUS* 


a/e 


N339 16/- 


TH4B 15/- 


VP2B 9/6 


GEX'in 15/- 
MAT100 f/8 


ll.ic. 


*/- 


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30PM 3/8 




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7/0 


P41 8/S 


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VP4 14/C 


iXXfl 


4/8 


1K1 1 


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BK31 


10/- 


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KATM1 8/6 




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i us u/c 


!-•■ on 7/3 


KN91 


s/e 


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MAT 120 7/B 


1F1 


5/9 


6F13 


4/9 


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X-.A.1 EC/9 




F.('C3'2 4^- 


EY31 


6/9 


i . -: is/a 


TPaa B/- 


PPtJO 11- 


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lrio 


4/8 


•.Kil 


23/3 


ion 9 9/9 


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ECC4J4 £1/7 


RY«l 


7/8 


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TPaa 6/- 


vpas e/e 


UA6 6c 


1P11 


5/8 


6F16 


6/9 


10LD3 6/3 


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KYW« 


B/3 


PC04 11/8 


TP2H20 17/8 


VI' 41 6/- 


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IRS 


4/- 


.11' I.'. 


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sen is/4 


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Ftf(.'4'l '/- 


F,Yt4 


e/a 


POB7 7/3 


1 VMS 11(8 


v i'!3.i e/e 


OA70 8|- 


1B4 


5/- 


BF17 


12/8 


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3.-.Z1GT 4/B 


CY1 16/4 


nx'-i 8/6 




6/9 


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t/ABcag 5/- 


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0,\7:i 8/- 


ia& 


3/6 




13/5 


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ao -" 4/n 


i : v •"■ 


a/e 


pccss e/e 


UAP4S 7/- 


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its 


£8/- 


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OA81 3/- 


1T4 


2/3 


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it's 


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42 6/- 


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1 


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OC140 19/- 


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5/3 




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4/9 


■ 


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6/6 




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in 10/e 


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. 089 5/9 


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4/6 


BBM1 


4/- 


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M D4J 9'- 




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KT41 


7/6 


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i'24 U/6 


M- 1 »7 14/6 


29/- 


HKK>'i 


4/9 


u^y7 


5/- 


19BO6OB0/6 


M-.'IH. 10/6 




: 11'- 7- 


KT44' 


6/- 


!'V-2 4(9 


*-■•.» 8/6 


M 127 P/6 


oosroa 14/- 


6HU0CS 13/6 


68 117 


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\V2vei, U/6 


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F.K-2 25-11 


KT61 


8/e 


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AIM 411 25/- 


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BREM 


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21- 


anni io/- 




KftliF 84/- 


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3/9 


PT88 7/0 


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tsjg 


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GU40T 


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9MM 81/- 


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Al 114 11/- 


DX641 10/- 


GBQ5 


4/6 




5/- 


90FS u/e 


AC4PBS 


I ■-.'. 10/- 


BOM 3/6 


KT74 


12/6 


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1: h 


6B<j7A 


7/8 


8U7D 


7/- 


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S7/£ 


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m -ci 8/e 


Kli- 


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(JI-21 6/- 


T37 89/- 


All 10 10/- 


16/- 


BBS) 


S/3 


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KIM 8/0 


KTwa 


4/9 


0P"22B 1£/C 


L'43 i/B 


\i ur s ; o 


vifidaAiE/. 


BBSS 


8/- 


i.vr.MT 


5/6 


2'>P3 ISf- 


DD 23/3 


KA50 1/6 


BUS 10/- 


K : I '«".;■ 


5/6 


QMS 5/- 


I,' li 16/8 


All 1- 20/- 


LS/E 


6B97 


36/. 


8X4 


3/9 20P4 13/:. 


AOIPEX 4/8 


K.A7G e/e 


EUG 3/B 


ETWM 


r/6 t»Hr.12fl 10/d l"J7 S/8 


AF1-24 11/- 


15/- 



WE REQUIRE FOR PROMPT CASH SETTLEMENT ALL TYPES OF VALVES, LOOSE OR BOXED, BUT MUST BE NEW 

METAL RECTIFIERS. I'llMll) 10/-. DR1I2B lad DRJtSB 15/8. LW7 21/-. 1.WI'. 24,-. KMO 7/11. Bill 6/3. 1U12 8/3. BUS 7(9. RM4 12/B. RMS 17/0, 14A80 
17/8. 14A97 19/6. UAIOti 23/-. I4A194 28/8. L4A168 35/6. MIll:io 31/-. L4BS61 11/9. Pi 101 10/3. 16RC.L1.16.1 S/-. FC3] 21/-. IIRD.'iJi.S.l 11/-. 10HI . 
8/6. 1BRA.1.1.SX 4/-. 1-.UA.1.2 -. 1 11/-. IV I Li B/-, PC»4 12/8. *B3 10/0. CtO 9/-. K3/40 9/-. CSD 11/-. C3B 14/S. Kit at) 4/3. Q:; 4 3/7. KS'tW li)/4. 
ELECTROLYTIC8. Oio lypcK 39 t 32(4.".0v. 5/9. 50 s BO/SSOt. 7/-. Hi x 120'SSOv. 3/3. 0O s B0OO7ST. B/6. 100 I 400 27'.v. 12/8. 106227."^. 8/-. aOO» n 7Sv. 4/- 
100 i B0O.270V. e/S. Tubulin: liptt: 84Bt,v. 1/0. lii(45uv. 2/9. :i2 430v. 3/0. » X S(4S0r. 3/-. 16 x 1043OV. 4/-. 32 % 32'SSOv, 4/-. • v I8/4S0T. 8/9 
MUXLAED Kiieet silioon reotifisw. Typrn 3Y100. Output 988 volu J nnip. So lamer 'han a shin bvttoa "/- each, i^eric" lituiiiii.* rciWunce ].'«. 

EXPRESS POSTAL SERVICE! ALL ORDERS DESPATCHED SAME DAY AS RECEIVED 

Timril of InnMlnm' rttfi irtHi ooliir urmn nnlj . U.D. s.a extra. AJI irutrv dviir - ;. Any 

parcel uuurtd Agmfiurt daroAgf in truult /or 8d. eitrft, tv.. tn 10 8 . 80 t.-ui Bku. f^SO^I p.m. Complete- Jist o( Euoi'lem *ui,l obsolete 

vklvca, rvairtort, conJeosen, tnmrotmcrj. pgteciiomrtrrs. rjiiLTiipliooem etc. with i«rm« ni trndmewi, ltd. Ple*« euquir- fgr any Hem KM Hated m'h S.A^B. 



August 1964 



PRACTICAL WIRELESS 



305 



SURBITON PARK RADIO LTD. 



ALL ORDERS DESPATCHED SAME DAY • WE PAY POSTAGE and INSURANCE 
MONEY REFUND GUARANTEE 



LEADING STOCKISTS OF MARTIN RECORDAKITS AND AUDIOKITS 



MARTIN RECORDAKITS 

HALF TRACK 

TAPE AMPLIFIER FOR STUDIO DECS with rea.iy 
wire.l printed circuit, control and Input panels, mains 
and output transformers, knobs, plana, imvi, etc. 
EF8»J, ECCoS, EZ.S0, EMSft and 2 ELW. 3 watts 
output. Magnc eye. Radio and Mlc. inputs, ext, speaker 
socket, tone and monitor controls. Dan be used as an 

atuulitlcr 611.U.0 

COLLARO STUDIO DECK. Very latest model, 3 speeds. 

Tin spools. £10.196 

CASE tor above -with 8 i Bin. speaker, two-tone grey 

£5.5.0 
COMPLETE KIT with tape and microphone, ., .229.0.0 

QUARTER TRACK 
COLLARO STCDIO DECK ::ued with Marriott "X" 

head* £17.17,0 

TAPE AMPLIFIER FOR STUDIO DECK a* described 

above but quarter track £12.12.0 

CASE with speaker, two-tone grey £0.5.0 

COMPLETE KIT with tape and mteropboue £35.0.0 



BRENELL TAPE EQUIPMENT 

DECK Mk. 8 8 >ries 2, halftrack, 4 speed £38.11.0 

AMPLIFIER tor above with power pack. . , . 126,0.0 



Dep. 


* 


Mthlv, 

pons. 

of 


24/- 


12 


19/- 


22/- 


8 


87/8 


5S/- 


10 


46/2 


87/6 


13 


89/5 


27/. 


IS 


20/8 


70/- 


u 


58/2 


86/- 
62/- 


If 

12 


54/- 
' 43/2 



MARTIN AUDIOKITS 

The new Martin All Transistor Teh Watt Amplifier 
Kits represent excellent value for money. Each unit is 
complete, requiring only to be connected to toe next. 
We show the most popular units here. Others are 
available. Leaflets on request. 

TJKIT 1-FIVE INPUT SELECTOR. 9bte 34 x 31n. 
Mag. Ft', Crystal PI . Radio. Mlc. Tape head, 9-16 
Volts, Mutt be used with unit 4 . . . £2.7.6 

UNIT 4 -FEE-AMPLIFIER AND CONTROL, tj i lijln. 
Volume on 'Off, bass and treble controls, 9-15 volts. 
Must be used with unit 1 . £8 2 8 

TJK1T 7-MAIH AMPLIFIER 10 WATTS 6 transistor 
transformerless push-pull output. Mounted on heat sink. 

IS uluus output. 24 Voils £8.12.8 

UNIT 6 POWER SUPPLY. 24 and 8 Volts. Heavv dm* 
trausiurtuer. rt-ct trier and smoothing £215 

CONTROL PANEL (or unJU 1 and 4 10.8 

ALL POUR ABOVE UN ,TS WITH PANEL. 15 ohms 

outpnt £15.8.0 

TJH1T 6 MAIN AMPLIFIER as Lull 7, 3 ohms output, 

-'* Vults £5.12.8 

UNIT S POWER SUPPLY as I' nit 3 for use wilt, 

£2.12.8 
ALL FOUR UNITS (1458) WITH PANEL. B ohms 

output £14.5.0 

STEREO VERSIONS NOW AVAILABLE. 
DETAILS ON REQUEST. 



33/6 



28/6 12 



Mthly 
1 pmts. 



25/3 



23/7 



GRAMOPHONE UNITS, MOTORS, 

Decea Deram Arm anil Plug-:n Shell £5 5.0 

Decea Deram Transcription Cartridge 14.14,8 

Decea Deram Auto Cartridge £3.1 '1.6 

Garrard SRP10 with Mono cartridge, single plaver 

£5.9.11 
B.S.R. UA14 with Tt.'d Mono Cartridge, 4-.-p. «d 

i- hanger £16.19.8 

Garrard Autoslim. Mono cartridge. 4 (peed changer 

£7.17.0 
Garrard ATB Auloilim de Luxe, TC8 Mono cartridge 

£11.9.0 

Garrard 4H/F with Muuo cartridge £17.0.0 

Garrard Lab Type "A" Transcription auto-changer, 

a iih Mono cartridge £19.14,9 

Garrard 301 Strobe £22.0.0 

Philips AG 1016, Stereo cartridge, will change Tin. 

records (adaptor ltt|- extra) £12.12.0 

Goldrlus GL58 with arm, lens cartridge £17.1.8 

Goldriog GL70 with arm, no can ridge £27.9.4 

Goldrme "38" Transcription, nu arm £18. IS. 5 



PI 


CK- 


^ 


~ 


20/- 


s 


20/- 


7 


26/8 
84/- 


9 
12 


39/6 
44/- 


12 
12 


27/- 
38/- 
65/- 
41/- 


12 
12 
12 
12 



32/9 
38/6 

20/3 
28/2 
45/6 
31/1 



ARMSTRONG - NEW TUNER AMPLIFIERS 



MONO 

AF20SA..M P M. Radio chassis, bass and treble er-ntMls, 

P.I Inputs, etc £21.4.0 

227M \ vi K.M.I'..!-;, :.>..< to watts £33.18.0 

223 A.1I.K1 Self-powered iTuneronly) .. £28.15.0 

224 F.M. only, 8elf-powered Tmier £22,10.0 

STEREO 

227 A.M. P.M. Radio chassis. Stereo gram. 10 watts 
each chain..- 1 £48.15.0 

228 AM. F.M. Kadin chassis. Stereo grain, 10 watt* 
each channel, Filter. Magnetic pick-up, etc £56.0.0 



OTHER TUNERS 

Tripletone F.M. Tuner, lesa power £13,19,6 

Trtpletons F.M. Tuner, sell-powered £15.14.6 



46/- 
70/8 
57/8 
45/- 


12 

12 
12 
12 


67/6 


12 


118/- 


12 


28/- 
31/6 


12 
12 



34/10 
56/1 
47/9 
37/4 



81/1 
93/2 



23/2 
28/1 



STEREO AMPLIFIERS-VARIOUS 

Armstrong 222 Integrated, luW per channel. .£27.10.0 

Dulci GA505, Integrated £18.18.0 

Rogers Cadet Mk, 2 with pre-ampiitler. 4 BCL86 

valves , £28.15.0 

Leak Stereo 20 Main amplifier £30.3.0 

Leak Varislope 2 stereo pre-ampliner £25.0.0 

Quad 22 Stereo Control Unit £25.0.0 

For Quad Main Amplifiers see Mono section. 



55/- 


12 


45/3 


40/6 


u 


31/1 


33/6 


12 


44/5 


rH/fl 


12 


50/3 


50/- 


L2 


41/6 


50/- 


12 


41/6 



MONO AMPLIFIERS 

Linear L45, :i w*t t . I valve 

Linear Diatonic, U watt, suitable Mlc. or Guitar 

£12.12.0 
Lineal Cooeiord, 30 watt, Ideal Guitar amp,, with 

cover , ,, , £18.0.0 

Dulci AS. integrated itnf..,i watt, W 'Lpii valve £13.2.6 

DuklDPA15, IS wan wiib-J-valvepre-amp. £28.5.0 

Tripletone Hi-Fi Major with pre-amp. Suitable f.-.r 

miliar or Mlc. etc. £15.18.9 

Leak TL/ 12. Ill watt Main amp. only £18,18.0 

Leak Varislope Mono pre-amplini-r. £15.15.0 

Quad. 13 watt Main atnplilier only £22,10.0 

Quad. preamplifier. Mono £19.10.0 



(5.19.6 I — | — I — 



1 — 


— 1 


27/- 


12 ! 


38/- 
£8/6 
52 6 


12 
12 
12 


35/3 
40/6 
31/6 
45/- 
39/- 


12 
12 

12 
12 
IB i 



20/8 

29/10 

21/6 

43/6 

28/1 
23/1 
26/1 
37/4 
32/4 



JASON F.M. AND TV SOUND TUNER KITS 



PMTl. complete with 4 KKHl valve- £7,4.8 

FMT2, leu. power, complete with 4 Kl'so valves 

£9.4.6. 
FMT2, with power, complete with 4 EFfti and 1 

EKSu £11.4.6 

FMT3, Fringe. ■ "triplet S with valve*, le?* power £10.19.0 

FMT3. with power, ■iiiipkie withal) valves £12,19.0 

JTV/2. switched F.M. and TV sound, self.powened, all 

valv-s £15.12.6 

Mercury II, a» JTV'2 but lews powei all mtva* £11.0.0 
Instruction book included in all ktti. Available separately. 
2/6 switched 3/6. 

JTV/2 ready built, stale channels £22.5.0 

Mud: ior. ready built as Mercury II £16.15.6 



81/- 


7 ■ 


20/- 


9 


22/8 
22/- 
26/- 


8 1 
12 


33/6 
22/- 


12 
3 


44/8 
33/8 


12 | 
12 I 



20/6 

eo/e 

24/9 
27/3 
21/6 



36/11 
27/9 



LOUDSPEAKERS 



Goodmans Axiette £5.5.7 

Goodmans Axiom 10 £8,5.11 

Goodmans 5K/20/XL £7.7.0 

Goodmans XO 5000 omtl BTir £2.0.11 

Goodmans Axiom 201. lain, unit , £10.17.4 

Goodmans Axiom 301. lain, unit , £15.4.6 

Wbarledale Super S/RS/DD £6.14.2 

W.B. HP1012 lllin £4.7.6 

FANE lata. Unit, SO watt £6.6.0 

Wbarledale W12/EG Itiln. 16 watt Lead Guitar 

{Maker £10.10.0 

Wbarledale W16/EG loin. 15 watt Bats liuitar 

speaker , £17.10.0 

Wbarledale Super 10/RS/DD lOin. high quality 

unit £10.18.0 

Wbarledale RS/12/DD IStn, 10 uati Hi-l'l. .. £11.10.0 






22/5 
30/6 


12 


17/11 
25/3 


21/- 


12 


17/6 


85/- 


12 


28/- 


23 'S 
27/6 


12 
9 


17/11 
24/9 



SURBITON PARK RADIO LTD. 

4ft, SURBITON ROAD, KINGSTON-UPON-THAMES, SURREY 



EASILY REACHED BY FREQUENT FAST TRAINS 
FROM WATERLOO TO SURBITON 

• Order for Cash, C.O.D. or Terms 
Hours 9 a.m. -6 p.m. (I p.m. Wed.) 
Open ALL DAY Saturday 
<3 Established 30 years 



Phone: 
KIN 5549 



306 



PRACTICAL WIRELESS 



August, 1964 



^lillMlllllllllllillllllilllllllllllNllllllllllllllllllliM 

| Lewis I 
i have the I 
I Cabinet 

| iiiiiiiiiiiiiiiimiiiiniiiiiiitiimtmmii | 

I for you 

E We can supply any cabinet p 
If to your own specification = 

= This is only one example of — = 
1 THE LARGEST RANGE = 
1 OF CABINETS IN THE j= 
| COUNTRY 

|§ Equipment is also our 

S speciality. = 





The Lowboy 
Price 27 gns. 



p imtmiii iiiiimiiiiiiitmiiiiiiiiiiiiiiimiiiiimi^ 
LEWIS 



= IOO(P84) Chase Side, Southgate 
= London, N.I4, Pal3733 9664 

| ^fljC^ CATALOGUE 

= Send today for the new 
= Lewis Catalogue 

5E Designed to assist your choice or 

= cabinet. 

= Sent absolutely Tree. The new Lewis 

BE Radio Cabinet Catalogue— the moat 

s comprehensive ever prepared. Choose 

~ from 49 different Models. 

= Please send your new free 34 page 

= colour cabinet catalogue. 

= Name .. 
= Address 



PADGETTS RADIO STORES 

(II. II TOWN II ALL. KNOWLKR HILL 

i.n f.kskim.i:. vorks. 

Telephone: Cleckheftton 2868 
Motors remn\ed from Wii-diinRMaeltlnei 
Fully guaranteed. 23U volt. 1 h.p.. 25/-. 
Carriage B/-. 

Hoover Motors 1/6 li.n. Complete with 
Drive Pulley. 15/-. Carriage 6/-, 
Homer Pump. 7/6. Post 2/6. 
New Ho.xeU Drive L'nlt Type 114, Com- 
plete with 5U4. 6L5, VS210 two KF50. one 
VRQ2 valves. Also 25 cycle tuning fork. 
Housed In very nice case. 16/-. Carr. B.R.S. 

W- - 

New ISIn. Speaker Willi Built-in Tweeter. 

28/6. -i ohms. Post free, 
tlnrk III Army Set. Type 19. Receiver side 
beach tested on phones. Sets as new. 50/-. 
Clean condition. 3B/-. Carriage B.R.S, 10/-. 
Simple drawing with each set explaining pin 
connections for mains operated power pack. 
This set will not transmit. 
New Volvo* Kx l-nlls. POST FREE. 
GX7 UQ each. doz. 12/-. BKB 2/8 each. doe. 
22/-, 0V6 2/6 each. doz. 22/-. B07 U.S.A. 6/-. 
PP3/250 (PX41 5/-. AC2PEN (PBXAi) 2/6, 
5U4 3/-. 6V6GT 4/6. EF91 1/0. EUB1 1/9. 
GFB 21-. 5Z4 5/6. SY3 4/6. 6X5 4/6. Er50 1/-. 
67- doz. AHP12 1/6. a for 5/6. box of 50 IB/-. 
KT66 8/-- ARTP2 2/-, ART4 2/-. AHP37 2/-. 
ARt) E/-. JT1 2/-. G54 new boxed. 1/3, 
13 Channel TV set*. Hln, untested 30/-. 
carr. 10/-. 171n. untested 50/-. carr. 10/-. Well 
packed, sent at owner's risk. 
T.V. Tunes. Complete rebuilt and re- 
raced. 12 months' guarantee. Sizes up to 
17in. Special trade price of 75/-. Carr. and 
Ins. 7/6. 

RECLAIMFH TCItF.S 
Mullard 12 and 14, Mazda CRM141-2 at 17/-, 
carr, 7/6. Mullard and Mazda 17in., 30/-. 
6 months' guarantee. _ 

P.M. Speakers. Guaranteed ex T.V. Sets. 
Bin. round. 6 x 41n. Rolaand Plessey, Philips 
51n. round, all at 3/- each. Post 2J-. 6 for 20/-. 
post paid. Goodmans 7 x Ha.. 5/-. post 2/-, 
Sin. round. 6/-. post 2/-. 
Valves Removed rrom T.V. Sets. Tested 
on a Mullard Valve Tester and are 100% as 
new. Three months' unconditional guaran- 
tee. POST FREE. 



ECLB0 


21- 


ECG82 


W- 


EY51 


B/8 


EBF80 


4/6 


EB91 


Wrl. 


EF91 


S)d. 


6SM7 


2/6 


6P1 


H- 


HF14 


67- 


8F15 


hh 


6LD2Q 


.6/- 


toes 


fi/- 


10F1 


1/- 


wpia 


hh 


10P14 


bh 



20D1 


ok- 


20L1 


St- 


20PJ 


fi/- 


20P4 


8/6 


20P1 


r>/- 


L25 


f>/- 


UB01 


H/8 


U281 


bh 


U2S2 


67- 


tJ329 


5/- 


KT36 


6/- 


PL81 


IV- 


PL82 


61- 


PLB3 


5/- 



PL33 


4/- 


PL33 


«/- 


PY80 


,V- 


PY81 


4/- 


PY82 


6/- 


PCF80 


4/6 


PCC84 


4(6 


B38 


4/- 


N:j7 


5/- 


6U4 


6/- 


6P2S 


3/6 


6K25 


5/- 


6P2B 


3/- 


PZ30 


6/- 



EF80 1/6 or 10/- per doz. Grade II EFBO 
tor test purposes 4/- per doz. 



BLOCK CAPITALS PLEASE 

§iiiiiiiiiiiiiiii!iiiHiiiiiii(iiiiiiuimiiiinmiiiiiit^ 



it AtPiO MiOOKS 

TELEVISION & RADAR ENCYC. 

l'iiii!i*h>(l Price 30/-. Boo* Bargain 9/8 

INDUSTRIAL TELEVISION 

I'lilill-lu'tl Prlee 15/-. Book ICttrKiilil 4/6 
vi BRBO FOR IlkXtilNV 'Its 8/6 

lil-Fl for tii,»;i\M.ns 8/6 

sot mi it (im; tint hf.(;ixnf.rs 8'6 

VI I HO * AtOl STIIS h\ Itrlee^ 11/6 

i MORE about Loudspeakers b» itrlgg* 8/6 

( AI1IM:T 1 1 an i I hook h> Itrik'L'^ 8/6 
AT A GLAN't'K Valve and T.V. 

Tube eiinltulenlx 41- 

OSFILLOSCOPK Bonk 5/6 

t --!\(; nu Ofi'lllnseope 7/- 

()>.( it.i.(is<(>i'i: r:<|ii]|tmenf 5/6 

M l l.l. Mtll Clri-ts. for Audio Ainu. 7/6 

Mil. 1. ARO llel". Transi-it or Ciret*. 13/8 

EXTRA ICnuiitment Tape It reorder 6/6 
TRANSISTOR Circuits for Radio 

Control of Model* 8/- 

S Kiev It l\(. I'ranslsitor Receivers 8/- 

KLECTRONH Voveltles 5/8 

i;l.l( TlttlNH Gadcretn 5/- 
KADIO Valve IHitu "Wireless World" 8/6 

IIII.IWI l!S l.ulil. lu itadio 8/6 
MOIHCHN Transistor t.lrcutU for 

Beglanerfi 8/* 

Mt( .il Trnnslslors 5/8 

All* of 1 1 1 ni Sonles 5/8 

ABC i>r \l:iniieli-iii 5/6 

Altc or Missile t.uidance 5'6 

All hook* Include postntcc. Il~t S.A.K, 

SELRAY BOOK CO. 

fill II VTES 1111. 1,. II VV1>, BItOMLF.Y 
KKM, lei. Ht'Rslvvay 1818 




Hoovad in l.rautlfnlljr »lyli>a cabU»U offi-rlng 

torriiir porformitnCM; and very klgb totality 

raprodncUno, Hniii-ln (rrrlt* md »rrl»l for 

nscei tlon til all your favourite programtues. Fully 

pwteattgd. 

MODEL 55 (as llliitt.). Coven afedluni. Ixtng and 

Bhort wave*. Size B'io. «-, x 3-'iii. d. x -liiji. h, 

PRICE ONLY £7.17,8. V. * P. 6(6. 

MODEL 38, Similar dtruitry to atave bat covtrs 

Medium *mv< only, SiiC 7; in. w. v 3Jin. d. I *l n- 

It. PRICE ONLY £4.14,8. P. * P. 5;d, 

SPECIAL OFFER 
LIMITED QUANTITY 

HI OH ORADE TWO-3TAOE DRAM 
AMPLIFIERS 
Made by »erj weii-lcnown manufaetnrer. 
L'slni: a tloube-tt-puud maioB traiiBionn*r «iu ij 
tsolateil oha^Hi^l wilh tajipeti primary, full wave 
ixiiiUct cooled retainer, and Mullani ECLS3 
triiKle-pentode valve. 3 watt output. Repartle 
totie antl voltiiiie eontroU. Overall size 8 tin. wide 
x 31u tlecp i 4Jlu. high. Kseh amplifier Bran.1 
Sew ami teateti and aapplletl complete »ith 
valvi-. 3 I'hni ..'ii jiiii traiialnrmer and kaoi*- 

PRICE 49 /6 t\ A P. 41-. 

aultable BID, x Sin. Speaker 10/6, plui 2/8 P. « P. 

(ideal u an add-on sell retttalned Audio unit or 

.ir MKI or MK'J I'M Tuner). 

BRAND NEW 3 OHM 
LOUDSPEAKERS 

ajuj.. LB/8; 5ln., LS/8; fl|U>.. IS/-; Bio., Blf-; 
Itiitt., 251- : tan., 27/6: llitta. 15 ohm 30/- 1. 

lOln. x itln. 8fl(- 

Latest type E.M.I. 131 * Sin. with high dux 
ceramic magnet, 11.000 nauss. Aluminium ccu'.r 
coae. 10 watte. 50 cfa to 10 Ke't.. 48/-. 
P. k P. up to tlin. 1 '«; over Sin. 2'6 per speaker. 

SPECIAL OFFER ! ! 
BRAND NEW HEAVY DUTY 12 in. SPEAKERS 
Response 45 c/a-13 kc.'jj. l|in. voice coll. Avail- 
able In a or lo tilim. Guaranteed full 15 iraita 
Biitltth rating. Heavy cast aluminium frame. 
These are current production by wnrlti famous 
maker and an they are offered well below Hat price 
wp are not permitted to dlscloae the name, 
LIMITED XL'MHKR ONLY. ISHEPEAT- 
ABLE AT 88/6, P. k P. PK 

SPEAKER AND CABINET FABRIC 

Oulunal ttr Ret] and Hold Yjnalr (or apeakpr 
and I'lo.itirt envertn(, aUki Ktil Keilue <• t 

.uly. All M*n. wki( and uaually eold at 
N ■ yard. -tq/C 
OUR PRICE I O / O p* r j-» n | u-ttfoh. 
plu* ]•. A \\ 1 'ft. ■ Mir urn ..r.lrr 1 yardj. Send 

- . I ■■ -i -ail.l.lr-. 

BARGAIN OFFER CORNER 

SOLA 0ELEST1ON. Approx. 9lu. i tin. 3 ohm. 
Middle reglnierntM-aket-. 10/6. P. 4 P.tW. 

MAINS TRANSFORMER 

Drop thnt' type. Tapped primarv llov.. HOK 
220v., -ittiv., 3aO-0-3Mv. at SOmA an 
at 3 onipa. Generous core. Stack alze Stx -] K 
l|ln. Weight 4 Ihs. USLY 15/-. 1'. A I'. J " 
ACOS CRYSTAL MIKES, High Imp. For deitk 
or band u*c. High 'sensitivity, 18/6. P. * P. 1/6. 
TSL CRYSTAL STICK MIKE. listed at 411/-. 
Our price 18/8. P. a P, !/«. 
T.C.C, SUPPRESSOR CONDENSERS. 'J00 v. A.C. 
.U0S + .006 X .1. In tubular ean ljio. Juuf i 
iiu. .liu. a lor 8/-, Peal (rise. 

TRANSISTOR DRIVER and O/P TRANSFOR- 
MERS. (Tapped 3 ohms auU la ohms output!. 
plus 4 suitable Transistors giving appro*. 1 watt, 
output, 30/-. P. Jt P. Sjk 

CONDENSERS. 8,00(1 jniM. U v. wfc*. 31if 
3 x Itn. ilia, il- each. P. * I'. Ed. each. 
BRAND NEW PLESSEY 1« v. 4 pin nou-syn.' 
vibrator*. Type IS 1.43U. ONLY 8/8. P. A P. 
1-fi eacb- 

8-PUSH BOTTON SWITCH UHIT. J sittele pott- 
ebaageover on each pnsb-buttan. Appeox. 
:i x 1} x iln. Aii aiisulutc Bargain at 4/6 eaeh 
I', a P, U- fftch, 

MARCONI 8.0ARTZ CRYSTAL TYPE3 ZHH. 
Still hvatlAl>li- a- prerloi^l> a4rartlMd. 



Harverson Surplus Co. Ltd. ^ 



August, 1964 



PRACTICAL WIRELESS 



307 



3-VALVE AUDIO AMPLIFIER 
MODEL HA34 

iJe-isned tor Hi-Fi 

records A-C Wttiili 

opeTatiuti. Keady 
■,iLnr -.a placed 
Itrw*. y gauge (petal 
ctifB&a$, -ii/.tf 7 'in. 
v,, v^iti- d. \4iui. a. 
Incorporates LuC Csm. 
EliBi* BKSfl Mil-. M 
bOW; fiuiy anii'i.lr-- 
wnutid mains fcrafiaiQUUer and uuLpuc transformer 
maU'hed for 3 ohm speaker, separate Bass* 
Tre hie and vo lume eonl ro 1 ti - NV^at l v e r e -: d La t ■ k 
line. Output 4i watts. Jfrunt panel can be 
d^tatlied aiid leads eitended ior remote moulding 
of cootryJa, 

The ILA34 hag been specially designed for us and 
our qo&tttfty order enables us to offer them 
complete with knobs, valves, jgA C A 




& p. 



h-cd and tested tor on:; 



TAPE DECKS 

COLLARO STUDIO DECK. SIO.10,0 plug S/8 
earr. and ins. 

B.S.R. MONARDECK. Binde speed, 3fia. per 
sea., simple control uses oftm spools, £3.15.0 plus 
6J6 can. and toe. (Tapga extra c.n both.) 



STEREO AMPLIFIER 

Incorporating 2 ECL82s and 1 EZSO heavy duly 
double-wound mains transformer. Output. 4 watts 
per channel, FnU tone and volume controls. 
Absolutely complete. 




fff)) BARGAIN PRICE 

J 89/6 f - tP - 5i - 

Also available complete with two S i Sin. speakers 
tor only £5.10.6. P. & P. 5 6. 

6 TRANSISTOR AND DIODE 
SUPERHET 

A first-class 2 wavebands transistor supherhet 
# Printed circuit panel istze Si I 2?in.).ft 3 pre- 
aligned l.r'. transfarniers. % High-vain Ferrile n.d 
aerial. % All First-grade translators. # Car aerial 
winding. # Push-pull output. . AU parts supplied 
with simple instruct tons. 

All pacts sold separately. Set of parts if purchased 
at one time. 

only £4.5.0 5£* 

35 ohm speakers 

Suitable far use with afcretf. 2m. LioodmaLis. l.tej.l 
replacement lor must, p^-kti portable*) 8/ft 
o-u- 12/fi; 6Sa., 17f6; 7 * 4im. 21/-. 
t 1 , .St P. I'd per spea-tfr. 

Pot-table CABINET 

Bfeti approx, tb* £ s: b'i i 3Jtn. riuiLahle for above 

using ajic gpeafcer, a5/-. P. a F. •-' -■ 

COIL AND TRANSFORMER SET 
FOR TRANSISTOR SUPERHET 

3 I.F. Irausfonnisi'a, one oseillaior coll, tine driver 
transformer and wound Ferrite aerial unci., long 
and aerial coupling), 32/6 complete, post I . 
ti transistor printed ciroott board to match, 8/8. 
foil ad. circuit iliagiam I ij -.-Mia. 

SPECIAL 
TRANSISTOR BARGAINS 

AbL BRAND HEW 
BWt 13 (Matched Pair) 15/- 

of-Ti 5i- ocra ai- octs e/- 

PXA101 6(8 XAJ08 6/6 Vliilflp 12/8 

Set of Milliard il transistors. QC44, :!— OC4u, 
OC8 I II matched pair, OCSl, 25/-. 

EBISWAX MAZDA 
R.F.I Pack: 1— PXjklO*2 Mixer: 2— FXA101 
I.F. Amp.: (Equiv. 0<M4 and 01J45) 10/8 

R.F. S Pai-fe: a-PXAlUl I.F.;— PX AliW Use: 

1— rxATu-i Miner .....18/8 

L.F.O Pack: IV.nsisting oi PXB1IJ llrii.-r. 
Matched pair PXC171, mounted comptele with 

heat sinks (F.quiv. OC81D and (X'fi]> 12/6 

A I.I. TEA.VSISTOP.S fUST FKER 



QUALITY RECORD PLAtER AMPLIFIER 
A tov-trnattty lweord placer aiuplitier. Mu 
Tin. w. I -J;in. ii. x ■■>}!«. h. This atiipllllei 

- 2fl «n. recotd pisv-ri employ t BCCB8 
BLU, LZiSti valves. Ka*> ti. I 

Coinpkrtfl with output tratis.ft.inur 
DWtetwO fur :i uhui jpeaker. Baady built and 

PRICE 69'4 P. & P. Vh 
ALSO AVAILABLE, Mmiim-il on board with 
■ .■ i - lj ■ : i Lr&jBsforJBCT nii.l liiTi. »|^aker. ready to 

III unocablncl I., l.-.v I'll U K 89/6. 1', Ji P. 4 ■! 

QUALITY PORTABLE BECOR'iTpVaYER 

CABINET 

Quest motor board, WtB take abovr BmpHll* 1 -m.| 

H.S.li. or UAKUAKD Autorhonser or niuijle 

Record Playnr i nil. Hn 18 * U at 8 m. 

PRICE £3.9.6 Cirr. S'-, 



Superior CABINET T» take H x oi". 
apoaher, with motor board will aivnonimodftte 
BBH I.AI4 or lAlli. £3,9.8. l.'Rir. J.'tl. Speaker 
10/6 Metis. 1". a I'. 1/6 extra. 
LARGE CABINET similar to above wltb 
speaker. S3.B.6. t.'arr. 5, 



4-SPEED PLAYER UNIT BARGAINS 

All Brand New In Makers' Original Packing 

SINGLE PLAYERS 

B.S.lt. XB/IS , £3.10.0. <:arr, H/fl. 

B.8.K. tib'T wlib unit mounted |ilrk-tt|i arm 
£4,18,8. Dm. 4,-. 

AUTO CHANGERS 

B.S.lt, I'AM £6.18.6 

Latest B.8.R. UAlli £6.19,6 

Garrard ATH Mono ,£10.10.0 

LATEST GARRARD AUTO-SUM. With heavy 
dotv, 4- pule motor, rtf ONLY £7.7,0. (Standard 
Ant'o-rtlim £6,10.0), OUT. .". ■ 00 each. 



NEW CARTRIDGE BARGAINS' 

B.S.R. TCSS. ii -: .,i. :..in|Mi:l.le Stereo 
Cartridge. Brand new. Complete with SiereO' 
LP 7s sapphire stvlH and universal mountltig 
bracket. Original pHce 44 11, OUR PRICE 

EONETTE STEREO 106 CARTRIDGE. Stereo; 
LP 75. Complete ^^ it h two sapphires. Original 
li>i price 87/B. OUR PRICE 2*1-. P. * P. I - 
COLLARO HL-FI STEREO T/O CARTRIDGE. 
Tvpe "C". Complete with universal bracket and 
sielii tor 5t r.-.,, LP and 75. Original lift price 
59/8. OUB PRICE 26/-, P- .v P. I -. 



E.M.I. 4 apeed Player and P.U. 

FURTHER HUGE 
PURCHASE enables us 
to otter these at 

4 P. 



67/6 



4 ii. 
Heavy 6] in. nxtal 
turntable 

performance •-HI* J.'iO 
c shd.L-'.l mottir with 
lap at 45v. iiir 
atuplilier vahe lila- 
ment If mi|l<ml 
1'omoi i ii ni hi ad. 




THE NEW HARVERSON KIT FOR THE HOME 
CONSTRUCTOR 



i a j 



. II.-IL' 



1 




purpose A.t . 
matau 'juii.atov. 
AMPLIFIER KIT 
TYPE HSL 'FOUR' 
■i VALVE, 4 WATT 
USING ECC8H. 
EL84. EZSO 
VALVES 

Special lea lures In- 
clude: 

• Heavy duly double-wound mains tmacfora i 
«.lh ,-!-:. irnstatU- iwretn. • rfi.-parai.i- Bass, Tn-I.le 
ao.L \ nliline ijiu&ruls, KlviUB ftllly variable boOBt 
anil rut with itilnlitouu hisertlnu loss. # Heavy 
neKatlve iV.-iU,aek loop ufft 'i slaves enaurea high 
output at ,-xeelb'iil ijuality with very Low dlstor- 
Ood la. i.r • rtiiilutde (or use with giiKur, tiil.t-u. 
phone or record player • Provision for remote 
niooutinLj oi contruls or ilirect on chassis. # All 
t.hii. hullils i.nti:i a i-hansls size only 7 i i 1 1 . wldi \ 4iu, 
deep. Overall height 4||iti, • Ail a mrponi i.t- Rod 
\,cK-.= are I, rami new • Very .-hiu m ■■ -■ u,- - ■ 
i .os enable even the In* n peril- need ami- 
tciir to lonstnit-t with 100 % nuceess • Supplied 
.Louii.-l.ic with valves, otitput l.ratisforTuer til ohms 
oulvi, screened lead, wire, iiulu, bolts, solder etc. 
as to boy) fn (e P. i P. 

PRICK 19 JO a/- 

Cumprehetolve circuit diagram, practical layout 
and parts list 31/8 i Free with Kit]. 



SEE 

LEFT 

HAND 

PAGE 

I OR 

MORE 

ITEMS 



HARVERSON SURPLUS CO. LTD. 

170 HIGH ST., LYIERTON, S.W.19 CHErrywood 39B5 

Open all day Saturday Earty closing Wed., i p.m. 

A few minutes from South Wimbledon Tube Station (Please write dearly) 

PLEASE NOTE: P. & P. CHARGED QUOTED APPLY TO U.K. ONLY, P. & P. ON OVERSEAS 
ORDERS CHARGED EXTRA, 
SBSM STJMP£D ADBBK88SD ESVSZOP2 WITH ALL IMtOlfUSS. 



IQ/14 WATT HI-FI AMPLIFIER KIT 

uliiltty 
finished 
monaural 
amplifier 




glide hum, 

Separate inputs for mike ami grain, allow records 
and announcements to follow each other- Fully 
shrouded sectior. wound output transformer to 
match li-luQ speaker and independent volume 
controls and separate bass and treble controls are 
provided Bvtag load lift and cut. Valve line-up 
i EL* 4s, Rt'"OSS, El' SiS and F.7JH! rectifier. Simple 
Instruction booklet 1/B. (Free with parts). 
All parts sold separatey. OXLX£g^ QQ P. * P. 

Also available ready built and tested complete with 
standard Input jack sockets, £8.15.0. P. & P. 6/0. 



HIGH GAIN ^-TRANSISTOR 
PRINTED CIRCUIT AMPLIFIER KIT 
Type TAI 




• Peak output in excess oi IJ watts. • AH standard 
British components. . Buiit on printed circuit 
panel size t> x 3in. # Generuiis size Driver and Output 
Transformers. # Output transiormer tapped for 3 
obm ami 15 ohm speakers. 9} Transistors (GVETH-4) 
or al Mullard OCS1D and matched pair of OCS1 op) 
. 9 volt operation. # Hverythin^ supplied, wire 
bstiery clips, solder, etc, # Comprelieicsivc, easy to 
follow Instructions and circuit diagram l. 7 o (Free with 
Kiti, All parts sold separately. 

SPECIAL PRICE 45f- P. & P. 2'6 

Also ready built and tested, 52/6. P. & P. 
.4 pair of TA l» art ideal for strrta. 



HARVERSON'S F.M. TUNER Mk. I 




i-.'s. • OA.SI 
ed diode output. 
utuatur. . Altr 
> x Sin. glass). . 
»Ht quality rttains Lransformer . 
Valves used ECCSfl 



i|. I'tliic 



Fully dril 



parts sold 
£ one time 
liagram and 



completed tttnei 3 % 6 s -Vim 

-ii.iio-jil.-K . St.-l oi part^ ii f in 

£5.1B,B, plus B/6 P.F, and bra. f 

Instructions 1/6 post free. Mark II Version as above 

hut complete. wiLh mairic eve, front panei and 

brackets £6.12.8. F. & P. S/S, 

Mark III Version as Mark 1 but with output stage 

IKt'l,*2l and tone control. £7.7.0. F, * P. S/6. 

Handsome Metal Cabinets. Choice of Grey, Black 

or Urcen. To til Mark t, 25/-. P. A P. ii/fj. To fit 

Mark 11, 17/6. P. & P. 2 .'6. 



SPECIAL PURCHASE! 
TURRET TUNERS 

By famous maker. Brand new and unused. Complete 
Kith P<y*4 and I'CFSu valves, 34-SS lies 1-P 
Biscuits for Channels 1 to 5 and 6 and 9. Circuit 
diagram supplied. ORLY 25/- each. P.P. 2/8> 



F.M. TUNER HEAD 
Tuning range £8-100 
Me la. ltl.7 Mc/s I.F. 
A permeabibty tuned 
tuner head by a famous 
maker, supplied without 
valve iECC£5) and drum 
and spindle. 18/6, plus 
1.9 P. & P. \alve 8/6 
extra. Drum and spindle 
3/6 extra, 




GORLER F.M. TUNER HEAD " 
&S-109 Ml'!. 10-7 Mc's I.F. 15/-, plus 1 9 ^ * P 
iECCSS valve. 8/8 estra.) 



308 



PRACTICAL WIRELESS 



August, 1964 




nv 



NOT BUILD ONE OFOUR 
PORTABLE TRANSISTOR 
RADIOS... 



BACKED BY OUR SUPER AFTER SALES SERVICE 



ROAMER SEVEN Mk 



S WAVEBAND PORTABLE OR CAR RADIO 

Amazing performance and specification 

9 stages — 7 transistors and 2 diodes 

Covers Medium and Long Waves, Trawler Band and two Short Waves to approx, 17 metres. 

Push-pull output for room filling volume from rich toned heavy duty 51n. speaker. Ah- spaced srnr.jjod 

tuning condenser. Ferrite rod aerial lor M & L waves and telescopio aerial for S Waves. Simulated 

hide case with gilt trim and -shoulder and hand straps. Size 9 x 7 x 41 n. appro*. 

The perfect portable and tile Ideal car radio, (Uses PP9 battery available anywhere). 

Total cost of parts now only jfC IQ A P. & P. 



Parts Price List and easy build plans 3'- 




TRANSONA 

PlYflT "Home Hah! A.F.N., 

I V ^L tux. alt at stood volume" 

G.P. Durham, 

© 7 stages — S transistors and 2 
diodes 

Fully tunable over medium and Lout 
Waves and Trawler Band. Incorpor- 
ates Ferrite rod aerial, tuning con- 
denser, volume control, new type fine 
tone super dynamic 2(in. speaker etc. 
Attractive case. Size 81 x 41 x liin. 
with red speaker grille. fUses 1289 battery available anywhere), 
Total cost of all AJ [JL P. & P. Ports Price Usi and easy build 
parts now only ~^/W 3^6 plans 2'- 

TRANSONA SIX 

# 8 stages— 6 transistors and 
2 diodes 

This Is a top performance receiver 

covering full Medium and Low 

Waves and Trawler Band. High-grade 

Ferrite magnet Sin, speaker makes 

listening a pleasure. Push-pull trans- 
formers for ample power. Ferrite rod 

aerial. Many stations listed in one 

evening including Luxembourg loud 

and clear. Attractive ease in grey 

with red grille. Size 6J x H x II lii. 
(Uses FF4 battery available anywhere) 
(Carrying- scrap 2/- ex.). 

Total cost of all CQ #Z P. & P. 

parts now only &'fV 3,5 

Ports Price list and eosy build plans I '6 



MELODY 
SIX 





, amazed ai volume and 
performance . , .has really come 
up la my expectations." 
S. G.. Stockton-on-Tees 

FREE! Miniature Earpiece, plug and socket {value 9>(t) and 

detaih of conversion to private listening. 

9 6 stages— 6 transistors 
and 2 diodes 

Our latest completely port- 
able transistor radio covering 
medium and long waves. 
Incorporates pre-tagged cir- 
culL board. 3in. heavy duty 
speaker, top grade transis- 
tors, volume control, tuning 
condenser, wave change slide 
switch, sensitive 6in, ferrite 
rod aerial. Push-pull output. 
Wonderful reception of B.B.C. Home and Light, 208- and 
many Continental stations. Handsome leather-look pocket 
size case, only 6} X Ji x liin. approx. with gilt speaker 
grille and supplied with hand and shoulder straps. 




Ports Price List and 
easy build plans 2'- 



Tocal cost of 
parts only 



£4.9.6 



p. & p. 

3'- 



POCKET FIVE 





SUPER SEVEN 



• 9 stages — 7 transistor* and 2 
diodes 

Covers Medium and Long Waves 
and Trawler Band. The Ideal radio for 
home, car, or can bo fitted with 
carrying strap for outdoor use. 
Completely portable— has built-in 
Ferrite rod aerial lor wonderful 

reception. Special circuit incorporating 2 RF Stages, push-pull output. 

3in. speaker (will drive large speaker). Size 71 x St x ljin. (Uses Bv 

battery, available anywhere). 

Total cost of all £\ IQ/ P. a P. Ports Price List and easy 



% 7 stages — 5 transistors and 2 diodes 

Covers Medium and Long 

Waves and Trawler Band, a 

feature usually found in 

only the moat expensive 

radios. On test Home, Light 

Luxembourg and many 

Continental stations were 

received loud and clear. 

Designed round su perse nsl- 

1 Ive Ferrite Rod Aerial and 

fine tone 2jin. moving coil speaker, built into attractive 

blaok case with red speaker grille. Size 5* x 11 S 31 in. (Uses 

128S) battery available anywhere. 

Ports Price List and easy build plans I '6 

Total cost of all A"} If. 

parts now only ^*f** P, & p. 3'- 

ROAMER SIX 

FREE! Miniature Earpiece, plug and socJeet (value 9 '6) ond 
details of conversion to private listening 

#8 stages — 6 transistors 



parts now only 



3'e 



build plans 2'» 



I 



All components used in our receivers may be pur- 
chased separately if desired. Parts price lists and 
easy build plans supplied free with sets of parts 
or available separately at fixed prices stated. 




and 1 diodes 

Listen to stations half 



world away with this S 
waveband portable. Tune- 
able on Medium and Long 
■ ; . Trawler Band and 
two Short Wave 3 . S e n s : t i ve 
ferrite rod aerial and tele- 
scopic aerial for short 
waves. Top grade transis- 
tors, 3-inch speaker, 
handsome case with gilt 
fittings. Size 71 x 51 x ljin. 



Ports Price List ond Total cost of all XA I Q A 

easy build plans 2'- parts now only fc "' ' * *** P. & P. 3'- 



RADIO EXCHANGE CO. 

61, HIGH STREET, BEDFORD. Phone: 2367 



Callers side entrance 
Barratts Shoe Shoo 
Open 9—5 p.m. 
Sots. 10 — 12.30 p.m. 



] 



August, 1964 



PRACTICAL WIRELESS 



309 



THE R.S.G. BASS-MAJOR 30 WATT GUITAR AMPLIFIER 




A MULTI-PURPOSE HIGH FIDELITY. HIGH OUTPUT UNIT 
FOR VOCAL AND INSTRUMENTALIST GROUPS 

Eminently suitable for bass, had or rhythm guitar and all other musical 

instruments 

•k Incorporating two I31n. heavy duty 2J-watt hlKti flux r 17,000 linos) loutlsiM-akei-s with 
2in. diameter speech colls. Designed for efficiently handling full output of amplifier 
at frequencies down to 25 c.p.s. 

*• Dual Cone (n second speaker reproduces frequencies up to 17,000 cp.s. 

* Heavily made cabinet of convenient size 2-1 * 31 x Min. has an exceptionally attractive 
covering in two contrasting tones of Vynair. 

ir For 300-334 v. to SO c.p.s, A.C mains operation. 

•k Four Jack socket input s and two independent vol, controls for simultaneous connection 

of up to four instrument pick-ups or ml crop hone*. 
1c Separate bass and treble controls providing more than adequate "Boost" or "Cut". 

* LEVEL, frequency response throughout the audible range. 
~k SUPERIOR TO UNITS AT TWICE TILE COST, 

"% fN ^m Send S.A.E. for leaflet. 

\ V 2 t a I"l C OR DEPOSIT of £4.3.0 and 13 monthly 
•* * ^"■■■*» payments of £3.9.11. Carr. 1TO. 



U.S.C. JUNIOR tilTTAR AMPLIFIER 

5- watt hiffli Quality OUtBUt. Incorporating 
high Btuc v.'.u: in « nt;, ::j.:.''0') line loudspeaker. 
Sensitivity 50 ui.v. High Impedance Jack 
Handsome strongly made cabinet 
(size 11 x 14 x 71b. approx.} finished in compli- 
mentary shadea of Rexine/Tygan, 200-2o0 
A.C. mains. 

f Q 1 Q C Or DEPOSIT 22/3 and 9 monthly 
*■<** I 3.Q payments of 22/3. Carr. 7/6. 

LINEAR TREMOLO/PREAMP. I NIT 

Designed for Introducing the Tremolo effect 
to any amplifier which is fitted with a 
reserve power supply point for smoothed 
H.T. aud 6.3 v. A.C. L.T. This applies to 
practically all amplifiers of oar manufac- 
ture, and to those of several other manu- 
facturers. The unit plugs into power supply 
point and any input socket or amplifier. 
Controls arc Speed (frequency of interrup- 
tions). Depth (for heavy or light effect). 
Volume and Switch. Three sockets are for 
switch. 
ONLY 



R.S.C. SENIOR IS WATT LEAD or 
RHYTHM GUITAR AMPLIFIER 

High-fidelity push-pull out- 
put,, Separate bass and 
treble "cut" and "boost" 
controls. Twin Separately 
controlled inputs so that 
two instruments or "mike" 
and pick-ups can be used at 
the same time. Loud- 
speaker is a heavy duty 
high Bux 12in. 30 watt 
model with cast chassis. 
Chassis is well made and 
finished as Junior Model, 
Size approx, 18 x 18 x 81n. 

0lUy 18 Gns. ST- 

Send S.A.E. for leaflet. Or DEPOSIT 37/9 
and twelve monthly payments of 31/6. 




GLASGOW - LONDON - EDINBURGH 



E"W AIM.VLE STREET '13* BOGWARG IUIAI* 

Three new branched rum uiicn 



133 l.i:il H STREET 



TRANSISTOR SALE, MuLlard OC71 3/9. 
OC46 4/11. OC44 4/11. OCT2 4/9, OC61 4/11, 
OC171 8/8. Ediswan XA101 3/3. XB102 3/9, 
XA112 3/9. XB113 3/9- XB101 3/9. XClfllA 
3/9. PoritfB (id. for up to 3 Transistors. 
!».€'. Si l'l>l,V KIT. 12 v. 1 a. consisting 
Of a partially drilled metal case, mains 
ridse Rectifier, 2 fuseholders 
■ ;:ii;t Direction switch, vari- 
ed regulator and circuit. For 
Wins. Suitable for Electric 
Trains. Limited number available at 29/11 



R.S.G. B20 BASS GUITAR 
AMPLIFIER 

A highly efficient unit Incorporat- 
ing a massive ISin. high flux loud- 
speaker specially constructed to 
withstand heaviest load condi- 
tions. Rating 23 watts. Individual 
bass and treble control a give 
ample "boost" and "cut". Two 
high impedance jack socket In- 
puts are separately controlled. 
All controls are conveniently 
positioned in a recess on top of the 
cabinet. Cabinet is of substantial 
construction and attractively fin- 
ished in two contrasting tones of 
Rexine and Vynair. Size approx. 
2i x 21 x 13in, Operation from 300- 

250 v. SO c.p.s. A.C. mains. 

Send S.A.E, for leaflet. 

29- GflS 0r De P° sit £3-2-0 &nd 13 



Carr. 17/6. 



monthly payments of 5178. 



keeeNii M 


RECTIFIERS 


(■'■■.v. BRIDGE 


24 v. 2 amp. . , 14/9 


6/12 v. la... 3/11 


24 v. 20 amp. . . 89/9 


6/12 v. 2 a. .6/11 


H.T. TYPES H.W. 


6/12 v. 3 a. .. 9/9 


150 v. 40 mA .. 3/9 


6/12 v. 4 a. .. 12/3 


250 v. 50 mA . . 3/11 


6/12 v. 6 a. . . 15/3 


250 v. 60 mA . . 4/11 


6/12 v. 10 a. . . 28/9 


250 v. 80 mA . . 5/11 


6/12 v. 15 a. . . 35/8 


250v. 250 mA .. 11/9 


CONTACT COOLED. 250 v. 75 mA. F.W 


(Bridge), 10/11. 250 


.'. 50 mA. F.W. (Bridge) 


8/11. H.W, 250 v. B0 


mA, 5/11. 


Ill-EI 10- WATT AMPLIFIERS. 



Brand New Complete {7 in e Carr. 

Units. * ' - ' ***» 5/6. 
Manufacturers' discontinued Model. Push- 
Full output. Latest hhrh efficiency valves. 
Dual separately controlled Inputs for 
"Mike". Separate Bass and Treble Controls. " 
Hhjh sensitivity. Output Tor 3 or 15 ohm 
speaker. Guaranteed tested and in perfect 
working order. I 



DERBY 



Now open at 

26 Os mas ton Road 

The Spot 



IIEAYI 1)1 IA Mil I>SI>KAKi:ilS i\ 
SUBSTANTIAL lilAIVi: ( OYEHED 

( VltlM.rs. Type BGL Suitable lor Bass 
Guitar. Speaker Unit 15tn., HlKli Flux 
15 ohms. 30 watts. Cabinet ,-izt- appiox 
21 x 21 x 151n. Only 195 c"-*. Or Deposit 
43/- and 12 monthly paymcnt-i Ol 54/.*, 
Type BG3/3. law itnJ Lead 

PWO 12in. high flux 18 ohm 25 wutl 
speaker.-., one with uuminium >pi 1 h oi 
and dual ronu nooth I'retniency 

response from 25 to 17.000 c.p.s. L'ablnt-t 
size approx, 30 .\ 21 x H In. Covered in two 
1 nir.i-.i-il:-;: tones ol icrey V'ytinu and 
Kcxmr. Rating 50 watts. Only 29 eii*. 
Or Deposit £3.7.8 and 12 monthly payments 
of 50/-. 

LARGE REXLNK COVERED SPEAKER 
CABINETS, Hear) blockboard 
tion. Very attractive two tunc covering 
ol Rexine and Vynair. Size JO x 21 x 16in. 
cut for lain, or 18ln. speaker 01 for two 
12in. 11 gn*« or Deposit 25/9 and 9 monthly 
payments a6/6. Size 30 x 30 x 161 n. cut for 
15in. or lBln. speaker 13riih. or Deposit 
30/4 and B monthly payments 30/4. 
Suitable speakers available. 

FANE EXTRA HEAVY DITT 
LOUDSPEAKER 151n. TYPE 158. 

40 watts. Total Mux 375.000 lines. Ex- 
tremely high sensitivity, 15 ohm voice 
coll. Only 18 ltn», or Deposit 37/9 and 
12 monthlv payments ©f 31/6. 
FANE EXTRA HEAVY l./Sl'i; AK1.K 
183. 18in.. 15 ohms. 60 watts. 31n. diam. 
Speech Coll. Total flux 375.000 lines. 
High sensitivity, ONLY 24 ffns. or Deposit 
S1J- and 12 monthly payments of 42/9. 
Send S.A.E. for leaflet on 153 and 183. 



Ex. fiOVT. SMOOTHING CHOKE'S. 

200 mA. 3-5 H. 50 ohms. Parroeko 8/9: 
150 mA. 10 H. 50 ohms 9/9; 80 mA, 20 H. 
900 ohms 5/9: 120 mA, 12 H, 100 ohms 8/9: 
50 mA. 50 H, 1.000 ohms e/9: 100 mA. 10 H. 
100 ohms 6/9: fcO mA. 5-10 H. 250 ohma 8/11. 

lOMI'LKTi: I'OU Kit !• VCK KIT. 18/11 
sttng of Mains Tians.. Metal RectP 
Ber, Double electrolytic, smoothing choke 
chassis and circuit. For 200-250 v. A.C. 
main?. Output 250 v.. K0 mA, f>,3 v.. 2 a . 

K.B.F. POWER PACK. 39/9. Louvred 
metal case only H x 51 x 2) in. Stove 
cnamclls-d. For 200-250 v. A.C. main''. 
Output at 4 pin plug and Booket 250 v. 
80 mA. fully smoothed and 6 3 lit. S ill 
able for power requirement* of almost 
any I're-amp. M Radio Tuner. 

U.S.C. ItAHY ALA KM or INTEIt- 

cini.M. KIT. Compici'. 1 set of pai 
diagrams, etc. Hou-sed in two poll.-hed 
walnut finished cabinets of plens'.ng 
design. Hlgn sensitivity. For SW-230 v. 
A.C. mains. Kuily isolated. Controllable 
at both units. An iaterromm. of this class 
would normally cost £20-£30. Olliy 8fl/6, 
carr. 5/- or assembled ready for use 6 gns. 




EX GOVT SELENIUM 
RECTIFIERS I2v IS AMP 
(BRIDGE) F.W. ONLY 



W9 



D C A (Hanchester) 



MAIL ORDERS to 54 Wellington St, Le*«*i I. Termi: C.W.O. or C.O.D. No C.O.D. under It. 
Postage 2/9 extra under £2. 4 * extra under £5. Trod* Supplied. S.A.E. with all enquirfe* pfeoi«. 



LEICESTER 
31 High St 

Half-day 
Thurtday 



BIRMINGHAM 
6 Gt. Western 
Arcade Opp. 
Snow Hill Station 
No half-day 



SHEFFIELD 
13 Exchange St. 
{Castle Market 
Bldjs.) Sheffield 

Half-day Thursday 



HULL 
51 Savile 
St. Hull 



LIVERPOOL 
73 Dale St. 
Liverpool 2 



BRADFORD 
56 Morley St. 
(above Alhambra 
theatre) Bradford 



MANCHESTER 
8- 1 3 Brown St. 
(Market Street) 
Manchester 2 



No half- day Half-day Wednesday No half-day 



LEEDS 

5-7 County 
(Mecca) Arcade 
Briggate Leeds 
No half-day 



310 



PRACTICAL WIRELESS 



Auyusr, 1964 



D © A (Manchester) 



MAIL ORDERS to 54 Wellington St, Leeds I . Terms: C.W.O. or C.O.D. No C.O.O, under £1. 



LEICESTER 
32 High St. 



Half-day 
Thursday 



BIRMINGHAM 
6 Gt, Western 
Arcade Opp. 
Snow Hill Station 
No half-day 



Portage 2 '9 extra under £2 

SHEFFIELD HULL 

1 3 Exchange St. i 51 Savi !c 
(Castle Market St. Hull 
Bldgs.) Sheffield ' 

Ha If- day Thursday 



4'6 extra under £5, Trade Supplied. 5.A.E. with all enquiries please. 



LIVERPOOL 
73 Dale St. 

Liverpool 2 

No Half-day 



BRADFORD 
56 Morley St. 
(above Al ham bra 
Theatre) Bradford 
Half-day Wednesday 



MANCHESTER 
8-10 Brown St. 
(Market Street) 
Manchester 2 
No half-day 



LEEDS 
5-7 County 
(Mecca) Arcade 
Briggate Leeds 
No half-day 



DERBY 



26 Osmaston Road 
THE SPOT 



FANE HEAVY DUTY HI-FI SPEAKERS 
12in. 15 ohms. Cast chassis. Exceptionally 
robust 2io. diam. Voice Coil Assemblies. 
122/10 20watt, 5gns. 122/10A20wart, 6gns. 
122n2'20wstt. Ssns. 122/12A 20watt. £7.19.6 
122/M22watt. 9gns. 122/14A 22watt, 10 gns, 
122/17 SSwatt, 11 mis. 122/17 A 35wa*fc, 12 gns, 
IMS. H ohms. Cast Chassis. Exceptionally 
robust 2in. dtam. Voice Coil Assemblies. 
ir,9.i i 2 20 watt. IS sns. 152/12A20watt, 13 gns. 
152114 27watt, 14 gns. 152/14A 27 watt, 15 ens. 
122/17 35 watt , 1 6 gn s . 152/ 17 A 35 w a tt . 17 ens. 
"A'' indicates dual cone type, 30-17.000 
c.p.s, Sand S.A.E. for leaflets. Terms 
available. 



R.S.C 30-WATT ULTRA LINEAR 

HIGH FIDELITY AMPLIFIER AI0 

A highly sensitive Push-Pull high output 
trait with self-contained Pre-amp. Tone 
Control Stages, Certified performance 
figures compare equally with most ex- 
. ■ ■ I amplifiers available. Hum level 
70 dB down. Frequency response ±3 dB 
30-20,000 c/s. A specially designed section- 
ally wound ultra linear output transformer 
is used with 807 output valves. All com- 
ponents are chosen for reliability. Six 
valves are used EF86, EF86, ECC33, 807 
807, GZ34. Separate Bass and Treble Con- 
trols are provided. Minimum input required 
for full output is only 12 millivolts so that 
AM KIND OF MICROPHONE OR 
PICK-UP IS SUITABLE. The unit is 
designed far CLUBS. SCHOOLS, 
TULA IRKS, DANCE HALLS or OUT- 
DOOR FUNCTIONS, etc. For use with 
Electronic ORGAN, O LIT AR. STRING 
BASS, etc. For standard or long-playing 
records. OUTPUT SOCKET PROVIDES 
L.T. and B.T. for RADIO FEEDER I NTT. 
An extra Input with associated vol. control 
Is provided so that two separate Inputs such 
as Gram and "Mike" can be mixed. 
Amplifier operates on 200-250 v. 50 c/s. A.C. 
Mains and has output for 3 and 15 ohm 
speakers. Complete Kit of parts with fully 
punched chassis and pqint-to- 
4-f fine point wiring diagrams and 
I i UII3. instructions. If required 
Carr. 10/- perforated cover with carry- 
ing handles can be supplied 
for 19/9. The amplifier can be supplied, fac- 
tory built with EL34 output valves and 
12 months' guarantee, for 14 gns. Send 
S.A.E. for leaflet. 

TERMS: DEPOSIT 33/9 and 9 monthly 
payments of 33/9. 

Suitable microphones and speakers avail- 
able at competitive prices. 

ARMSTRONG, DULC1, LINEAR, 
ROGERS, LEAK and JASON EQUIP- 
MENT, GOODMANS, W B. AND 
FANE SPEAKERS. GARRARD AND 
GOLDRING T TABLES CASH or H.P. 



I'.M. SPEAKERS. lOin. W.B. "Stentorian" 
| 3 or 15 ohms type HF 1012 10 watts, hi-fidelity 
. type. Recommended for use with our All 

Amplifier, £4.12-6, i2in. R.A. 3 ohms 10 watts 
' (12,000 lines). 59/9. 

TWEETERS. " rTa. 3 ohm. 25/9: 15 ohm, 25 /9 

I R.A. 121n. DUAL COVE 8 ohm 8 watt 
Speakers, Ideal Tor Stereo. Only 39/9 ea. 
.Jason inn V.h.k H'.M. Radio Tuner de- 
sign. Total cost of parts including valves, 
Tuning dial. Escutcheon, etc., Sc.19.6. 

LINEAR L4.V MIMA IT RE -J j WAIT 
QUALITY AMPLIFIER. Suitable for 
any record playing unit and most micro- 
phones. Negative feed-back 12 dB, Separate 
Bass and Treble Controls. For mains 200- 
250 v. 50 c/s. Output for 2-8 ohm speaker. 
Mullard valves EZBO. ECCffii. EL31. Size 
only 7x5x5Kin. hiprh. Guaranteed 12 months 
Only £5.19.9. Send S.A.E. for leaflet 
Terms: Deposit 22/8 and 5 monthly pay- 
ments of 28/8. 



SUPERHET FEEDER UNIT. Design of 

a high Quality Badio Tuner (specially 
suitable for use with our Amplifiers}. 
Delayed A.V./C. Controls are Tuning, 
W/Ch. and Vol. Only 250 v. 15 mA. H.T. and 
L.T. of 6.3 v. 1 amp, reauired from amplifier. 
Size approx. 9 x 6 x 7tn. high. Simple align- 
ment procedure. FoInt-to-Point wiring 
diagrams, instructions and priced parts list 
with Illustrations. 2/6. Total building cost 
£5.5.0. S.A.E. for leaflet. 



1--1IH. 



WAIT 



HIGH QUALITY 
LOUDSPEAKER. 

In walnut veneered 
cabinet. Gauss 
12.000 lines. Speech 
coil 3 ohms or 15 
ohms. Only £4.19.6 
Carr. 5/-. Terms: 
Deposit 11/3 and 
9 monthly pay- 
ments of 11/3. 
lain. 20 WATT 
HI-FI LOUD- 

SPEAKERS IN 
CAIHNETS. Size 
13 x 18 x lOin. Finish as above. Terms: 
Deposit 17/9 and 9 monthly payments of 
17/9. Only £7.19.6. Carr. 8/6. 
For larger types set- preceding page. 




LINEAR LG34 GRAM. AMPLIFIER. 

High quality. Separate Bass and Treble 
controls. Handsome appearance. Com- 
pletely enclosed. Black/Gold Frontplate 
5 go*. 



R.S.C, 4/S WATT A5 HIGH-GAIN AMPLIFIER 

A liiEhlj -sensitive 4-vafve quality amplifier for the 
home, small club, etc. Only 511 millivolts infill* is re- 
quired fur full output so that it is suitable for use with 
On- latest high fidelity pick-up heads, in addition to 
all other types of pick-ups and practically all "mikes". 
Separate Bass and Treble Controls are provided. These 
give full long-playing record equalisation. Hum level Is 
negligible being 71 <1R down, IS till of Negative feedback 
i- used, H.T. ol 300 v. 85 mA and L.T. of 6.3 v. 1.5 a. Is 
mailable for the supply of a Radio Feeder Unit, or 
S?"" I st|>r-I»i-ek pre-ampliner. For A.C, mains input of 200- 
Sld-'iio v. 5i| <•/-. Oiilpul for J-Sulims speaker. Chassis is not alive. Kit is complete 
in ri'-rj detail and includes fully punched chassis (with baseplate! with Blue 
Hammer iim-ii and point-to-point wiring diagrams and instructions. Exceptional 
value at unly £4.15.0, or assembled ready for use 35/- extra. Plus 3/6 carr., or 
dcpu-.lt flg/6 and .1 monlhly nayim-nt* of 22/6 for assembled unit. 




GLASGOW - LONDON - EDINBURGH 



3ai ARGYLK STREET 



S3K KDG1VAKE ROAD 



Three new branches now open, 

I.H.I . 



13a LL'ITII STREET 



THE SKYEOUK T.H.E. RECEIVER. 

A design for a 3 valve lone" and medium 
wave 200-250 v. A.C. Mains receiver with 
selenium rectifier. High gain H.F. stage 
and low distortion detector. Valve line-up 
6K7. SP61. 6V6G. Selectivity and quality 
excellent. Simple to construct, Point-to- 
Point wiring diagrams, instructions and 
parts list 1/9, maximum building costs 
£4.19.6, inc. attractive walnut veneered 
wood cabinet 12 x OS x 5Jin, 

R.S.C. BASS REFLEX CABINETS, 

JUNIOR MODEL. Specially designed 

for W.B, HF1012 Speaker, but suitable for 
any good quality lOin, speaker, Acousti- 
cally lined and ported. Polished walnut 
veneer finish. Size 18 x 12 x lOin. Handsome 
appearance. Ensure superb reproduction 

for only £3.19.6. 



STANDARD MODEL, As above but for 
121n, speakers. Size 20 x 15 x 13in. For 
vertical or horizontal use. £5.19.6. Set 
ol legs with bra ss ferrules, 19/8, 

R.S.C. II \I < >ir~HI-FI — REPRODUCER. 

The very latest Goodman Axiette 8 High 
Fidelity loudspeaker (retailing at approx. 
5 gns/) fitted In a specially designed Bass 
Reflex cabinet size 12 x 18 x lOin, Acousti- 
cally lined and ported and finished in 
polished walnut veneer. Matching im- 
pedance 15 ohms. Frequency 
range 40-15.000 c.p.s. Power o £nc 



handling 6 watts nominal. 
Ideal for Stereo. 



Carr. 4/6. 



R.S.C. BATTERY TO MAINS CONVERSION UNITS 



R.S.C, BATTERY TO MAINS 
Type BM1. An all-dry battery 
eliminator. Size 5 1 x 41 x 2in. 
approx. Completely replaces 
battery supplying 1.4 v. and 
90 v. where A.C. mains 200-250 
v. 50 c/s is available. Suitable 
for all battery portable 
receivers reauirine 1.4 and 
SO v. This includes low con- 
sumption types. Complete 
kit with diagrams, 39/9, or 
ready to use, 46/6. 



Type BM2. Size 8 x 51 x 21in. 
Supplies 120 v. 90 v, and SO v. 
40 mA and 2 v. 0.4 a. to 1 amp. 
fully smoothed. Thereby 
comnlefely replacing both 
H.T, batteries and L.T. 2 v. 
accumulator* when con- 
nected 1o A.C. mains supply 
200/500 v. 50 c/s. SUITABLE 
FOR \I.L It A I TER1 RE- 
CEIVERS normally using 
2 v. accumulators. Complete 

kit of parls with diagrams anil instructions, 

49/9. or ready for use, 59/6. 




MULTI-METER. CABV Ml, Sensitivity 
2.000 ohms per volt. A.C. and D.C., 54/-, 
A.10. Basic Meter sensitivity 155 micro- 
amps A.C. and D.C. ranges £4.11.6, H.40. 

Sensitivity up to 10.000 ohms per volt A.C. 
and D.C, £6.2.5. 30.000 ohms per volt, 
with overload buzzer, £8.19.6. 



R.S.C. CORNER CONSOLE CABINETS 

Polished walnut 
veneer finish. Fleas- 
lug design. JUNIOR 
MODEL. Size 20x11 
x Bin. for 8 x 51 n. or 
10 x Sin. speakers, 
£S.9.9. STAN- 

DARD MODEL. 
Size 27 x 18 x 
12in. for 8 or lOin. 
speakers. £4.11.9. 
SENIOR MODEL 
Size 30 x 20 x 15in. 
for 12in. Speaker. 
Suitable Speaker 
systems below. 
Only 7 ens. 




AUDIOTRLNE HI-FI SPEAKER SYS- 

TEMS. Consisting of matched 12in, 
12.000 line. 15 ohm high quality speaker; 
cross-over unit (consisting of choke, 
condenser, etc.) and Tweeter. The smooth 
response and extended frequency range 
ensure surprisingly realistic reproduction. 
Standard 10 watt rating £4.19.9. Carr. 5/-. 
Or Senior 15 watt, £6.19.9. Carr. 7/6. 



Al DIOTRINE 

EQUIPMENT 

CABINETS. 

Size 33 x 1.5 x 
18in. Beautiful 
walnut veneer- 
ed finish. Ele- 
gant contem- 
porary design. 
Robust con- 
struction. 
L'ncut, remov- 
ablebaseboard. 
Depth above 
baseboard 




Only 12< ens. 
Carr. 15/-, 



Terms: Dep. 29/9. and9mthlv. pymts. 29/9 



August, 1964 



PRACTICAL WIRELESS 



311 



AUDIOTRINE HI-FI TAPE .RECORDER KIT 25^' - 

REALISM AT IN CREDIBL Y LOW t OST. CAN HI ASSEMBLED l\ A\ IIOl K '" a 

Incorporating the lutes! Collaro Studio Tapo Transcrlptor. The Audldttinc High quality Tape Am: 
with negative feedback equalisation lor each of 3 speeds. Irish Flux P.M. Speaker, empty Tape Spool, a 
Reel of Best Quality Tape and a Handsome Portable CarryltiH Cabinet tastefully covered la con- 
trasting shades of Rexine. and Vynalr, size 141 x 15 x 8lin. high and circuit. Total cost IT purchased 
individually approximately £40. Performance equal to units in the EtfO-JiBfJ class. tj.A.i:;. for leaflets. 
TERMS. Deposit £2.13.9 and 12 monthly payments of 44/-. Cash price if settled in 3 months. 

ONLY a 

PAIRS OF 

SOLDERED 

JOIM> 

PLUS 

MAINS 



HIGH FIDELITY 12-14 WATT AMPLIFIER TYPE All 

PUSH-PULL ULTRA LINEAR „_ 

OUTPUT 'BUILT-IN' TONE 
CONTROL PRE-AMP STAGES 

Two input sockets with associated controls 
allow mixing 1 of "mike" and gram., as In A10 
High sensitivity. Includes 5 valves, ECCB3, 
ECGS3, EL.B4. EL34, EZ81. High Quality sec- 
tionally wound output transformer specially 
designed for Ultra Linear operation and reli- 
able small condensers of current manufac- 
ture. INDIVllil'AL CONTROLS FOR BASS 
AND TREBLE '-Lift" and "Cut". Frequency 
response - 3 dB 30-20,000 c/a. Six negative 
feedback loops. Hum level 60 dB down. ONLY 
23 millivolts INPUT required for FULL OUTPUT, 
type: 

dakd 

STRING BASS. LEAD OH ilHYTHM G LIT ARM. eli: 

OVTPL'T SOCKET with plug provides 300 v. 30 niA. and a. 3 v. 1.5 a. For supply Of a 

RADIOFKEHKR UNIT. Sizeapprox. 13x9 x Tin. For A.C. mains 300-250 v.SOc.p.s. Output 





R.S.C 6RAM, AMPLIFIER KIT. 3 

watts output. Negative feedback. Controls 
Vol.. Tone and Switch. Mains operation 
200-250 v. A.C. Fully isolated chassis. 
Circuit, etc, , supplied. Only 39/9. Carr. 3/9. 
HI-FI CRYSTAL PICK-UP HEADS. 
(Cartridges.) Acos Standard replacement 
for Garrard, B.S.R. and Coliaro, 16/9. 
Acos Stereo-Monaural. 29/9. Ronette 
Stereo-Monaural 39/6. R.S.R. Stereo 39/9- 

suitable for use with all makes and braomatk recording heads 

of pirk-ups and microphones. Comparable with the vers beat designs lor STAN- High Impedance Record/Playback 22/-. 

R or LONG PLAYING RECORDS. For MUSICAL INSTRUMENTS such as Low Impedance Erase. 12/6. 

MARRIOTT RECORDING RFADS, 
Hljrh Impedance. Record/Playback .15/-. 
Low Impedance, Kra->r. 10/- 



ior 3 and 15 ohms speakers. Kit is complete to last nut. Chassis Is fully punched. Full 

instructions and point- to- point wiring diagrams supplied. Only o (*•*» Carr. 

(Or factory built 51/- extra.) *», «"*• lp/ ; . 

If required louvred metal cover with 2 carrying bandies can be supplied lor 18/9. 1 l-.RMS 

ON VSSEMBLKl) UNITS, DEPOSIT 24/9 and 9 monthly payment* of 24/9- Send . 

S.A.E. for illustrated leaflet detailing Cabinets. Speakers, Microphones, etc.. with caah | 30/9, b.M3 with neck band and heavy table 



PICK-UP ARMS. Complete and with 

latest Acos/h:-fi Turnover Cartridge 2B/11. 
IHVSTAL MICROPHONES. Hand typo 
NP110 14/9. R.T.C. 19/9. Acos Mie 40 25/9. 
Acos Mic 46 25/9. Stick type Acos 39-1 



and credit terms 

LINEAR TAPE PRE-AMPIJITER. Type LP/1. Svvltchi'ii Negalive feedback 
equalisation. Positions for Record Lin.. 3Un., 7}in, nnd Playback, EMM Recording 
Level Indicator. Designed primarily as tile link tint ween u Collaro Tape I rim- 
scrlptor and a hiEU fidelity amplifier, but suitable for almost am Tape Deck. 
Only 9 gns. S.A.E. for leaflet. ^_^__^^__^ 

R.S.C. STEREO/TEN HIGH QUALITY AMPLIFIER 

A complete set of parts for the construction of a stereo- 
phonic amplifier giving 5 watts high quality output on 
each channel ftotal 10 watts). Sensitivity is 50 milli- 
volts. Suitable for all crystal stereo heads. Ganged 
Bass and Treble Control give equal variation of -lift" 
and cut". Provision is made for use as straight 
(monaural) 10- watt amplifier. Valve line-up ECC83. 
ECC33. EL84. EL8L EZ81, Outputs for 2-3 ohm speakers. 
Point-to-Point wiring diagrams and in- Qnc 
structions supplied. Send S.A.E. for leaflet "» *■•■«• 
Full constructional details and price list 2/6. Carr. 10/-. 
Kit can be supplied assembled and ready 10 use for 59/6 extra. 




stand 59/9- Lapel type 29/9, 
COLIARO JUNIOR 4-speed Single 
Player Unit and Crystal Pick-up with hi-fi 
Turnover bead. Only £3-19.6- 
II.S.R. I AM 4-sp ! d AUTO-CHANGERS 
with hi-fi turnover head, £6.19.6. Carr. 4/6. 
GARRARD AUTO-SLIM 4-SPEED 
AUTO-CHANGER with high fidelity 
pick-up. Latest model. For 200-250 v. 
A.C. mains. £7.17.6. Carr. 476. 
GARRARD AT6 AUTO-SLIM DE- 
LUXE 4-SPEED Al TOCHANGEHS, 
Turnover GCB head, for 200-3o0 v. A.C. 
mains, £11.9.0. 

GL3.Y MINIATURE 2-3 WATT GRAM 
AMPLIFIER. For use with any single 



or auto-change unit. Output for 2-3 ohm 
speaker. For 200-260 v. A.C. mains. Size 

• 111 x 2t x 2|ln, Controls: Vol. and Tone 

. with Switch. Only 59/6. 



SENSATIONAL 
STEREO OFFER 

A complete set ofparts a Qnc 
to construct of a good ^ «■'»■ 
Stereo amplifier with a 
■irted output total <> wait, 
For A.C. mains input of 20U-23U 1 
Sensitivity 130 ret. v. Ganged Vol. 
and Tone Controls. Preset balan 

Full Insti ucl 
wiring dia-sTaros supplied. Stereo 
PIcfe-inj Head 19/9 extra with above 
only. 



HEAVY DUTY CHARGER KIT, 

ti/rl i, b amgjs., variable output 

Consisting of Mains Transformer 
0-200-230-250 v. : F.W. (Bridgro Selen- 
ium Rectifier: Ammeter, Variable 
Charge Rate Selector Panels 
Plugs, Fuses, Fuseholder ant 
c 1 re 1 ;:'-. 5Ri'9. Carr. 4/6. 



R.S.C, BATTERY CHARGING 




\ — I MULCH 
4 tium- 6/i*i \. 
fitipti a tn 
to B i f r and 
v a 1 1 it h 1 e 
cliHtgo rate 

selector plug 
for 6 v. or 12 v. 
charging. Louvred 'teel case with scoved 
grey hammer finish. Fused and 
for use with mulns and output 
leads and battery clips, Cai 1 
Terms: Deposit 12/- and 5 monthly 
payments of 12/-. 



All for A.C, Mains 200-2SOv., SO e s. 
ASSEMBLED 

■i." I "- V. 2 HIIIDK. 

Fitted Ammeter 

-lector 



59/9 



EQUIPMENT Guaranteed 12 months, 

BATTERY CHARGER KITS 

ttg of Mains Traits- 
former. FAY. Bridge, ifetai 
Rectifier, well ventilated steel 
case. Fuses. Fuse-holders. 
Gramme ts, panels. Heavy Duty 
Clip.-, circuit. Can-. 3/ti extra. 

6 v. or 12 v. 1 amp 22/9 

As above, with Ammeter . , 83/9 

6 v. 2 antpK 19/9 

fl v. or 12 v. 2 amps 25/9 

8 v. or 12 v. 2 amps, inclu- 
sive of Ammeter 3S/9 

S f. or 12 v. i amps, with 
Ammeter and variable 
charge rate selector. 52/8 



ii.li'.' tor 

12 V. Louvred 
metal case fin- 
ished attractive, 
hammer blue. 
Fused, ready for 
use wit h rn; 1 - 
and output lead b. 

39/9 g* 

1/ttV. I amp. 27/9 

Less meter. 



t 'HARGER KIT, 11 v. M AMP or 24 V. T A.MP 

Consisting of mains trans. 20a-230-2"iO v. F.W. (Bridffei selen- 
ium Rectifier. Ammeter. Fuses, Variable Resistor, Heavy 
Steel Stove enamelled case and Circuit. Only £0.10.8. Carr. 
I'./-. Please state if 12 v. or 21 v. kit required.. 



1 1 1 A KG ER AMM ETERJ&* 

0-1.5 a., 0-4 a.. 0-7 a. 8/9 ea. 

CHARGER KIT, I2v. 10 Amp. 

with variable charge . rate 
adjustment and ammeter. 
£4-19.6. Carr. ID/-. 



R.S.C. MAINS TRANSFORMERS 



Interleaved and Impregnated. Prim- 
aries 2Ufl-230-'i.jO v, 50 c/a. Screened 
TOP SHROUDED DROP THROUGH 

250-0-250V. 70mA, 6.3v. 2a. 0-5-6.3V. 2a. . 17/9 
36O-O-.')30v. BOmA. 6.3T. 2a. 0-5-6,3v. 2a. . 16/9 
25O-O-250V. 100mA. 6.3v, 2a. 6.3V. la .. 21/9 
S5O-fl-250v. 100mA. 6.3v. 3.5a. C.T. . . 19/9 

2S0-0-250V. 100mA. 6.3v. la. 0-5-6.3V. 3a 2ij/9 
300-0-300v. 130mA, B.3v. 4a. 6,3v. la. for 

Mullaxd 510 Amplifier 29/9 

300-0-30CK-. I00mj\. B.3V. 'la, 0-5-6.3V. 3a 86/9 
3S0-0-35OV. 100mA. 6.3v. 4a. 0-5-S.3V. 3a 26/0 
350-0-3S0V. 150mA. 6. 3 v. 4a, 0-5-6.3V. 3a 29/9 
FULLY SHROUDED UPRIGHT 
260-0-3SOV, 60mA. S.3v. 2a, 0-5-6, 3v, 2a, 

Midget type 21 x 3 x 3in. . . ■ 17/11 

250-0- 250v. 100mA. 6.3v. la. 0-i-S.3v. 3a S7/9 
300-0-.300V. 100mA. 5.3v. 4a, 0-S-6.3v, 3 a 27/11 
30O-0-3O0V. I30mA. 6.3v. la. C.T. B.3v. 

la. for MuIIard Amplifier 33/9 

35(KI-350v, 100mA. 6.3v. 4a. 0-5-«.3v. 3ft 27/11 
3S0-C-3JKK'. 130mA, 6.3V. 4a, 0-B-A.3V. 3a. . 35/9 



ERS ( GU , 

L1A SHROt 



FULLY Y 

VltAN li:i:n/ 
FILLY SHROUDED (conl Iliued)— 
425-0-425 v. 200mA, Ov. 4a, C.T. Gv. 3a. . 55/- 
425-0-125V. 200mA, 6.3v. 4a, C.T., 6.3v. 

4a, C.T., 5v. 3a 59/9 

450-0-ISOv. 250mA, 8.3v. 4a. C.T. 6v, 3a, . 69/9 
OUTPUT TRANSFORMERS! 
Midget Battery Pentode 66:1 for 3S4, 

etc . . 4/6 

Small Pentode. 5.00011 to 3li .. .. 4/6 
Small Pentode 7/8,000 n to 3 tl ., .. 4/S 
Standard Pentode 6,000 El to .to . . 5/9 

Standard Pentode 7.000 u to 30.. .. 5/9 

lO.OOOti to 30 6/9 

Push-Puil 6 watts, MhB4, or QV$ to 30 

or matched to 15(1 9/9 

PuBh-Pull 10-13 watts to match HV6 or 

ELB4 to 3-5-8 to 15 U . , , . 19/9 

Following types for 3 and 15 fl speakers : 
Puah-Pull 10-12 watts 6V6 or EL8! . . 18/9 
til U-1H watts. 6L6. KTC8 . . 22/0 

Push' Pull MuIIard 510 Ultra Linear . . 20/9 
Push-Pull 20 watts, sectlonally wound. 

6L6, ICT6B. EI^4. etc 49/9 



MIDGET mains Primaries 200-250 v- 

50 c/s. 250v. (lOmA. 0.3','. 2a . . . . 11/9 

250-0-2JOV. 60mA, 6.3v. 3a .. 12/11 

Both above size 2i x 2j x 2iln. 

FILAMENT TRANSFORMERS 

All vith 200-250V. 50 c/s primaries 6.3v. 

1.5a.. 5/9: 6.3v. 2a. 7/6: 0-4-6.3V. 2a, 7/9: 

12v, la. 7/11; 6.0v. 3a, 8/11; 6.3v. Ga, 17/C| 

I2v. l.oa. twice, 17/6. 

SMOOTHING CHOKES 

150mA, 7-10 H. 260 ohm- . . . U/0 

110mA. 10H, 200 ohms 8/9 

BOmA, 10H, 350 ohms .=/9 

60mA. 10H, 400 ohms 4/11 

CHARGER TRANSFORMERS 

All With 200-230-250V. 50 n/s Primaries: 

0-9- 15v. lia, 12/9; 0-9-lav. 2a, 14/9: 0-9-15V. 

3a. 16/9: o-!>-15v. 5a. 19/9: 0-9-15v, 6a. 83/9; 

r-f-l5v. "Ra. 28/9. 

Al TO StiD tip/Steo ilowni TRANS. 

0-1 10/120- 23O/2S0v SO-80 watts. 13/9: 

250 watts. 39/6: 1M watts. 27/9. 

MICROPHONE TRANSFORMERS 

120: 1 high grade, clamped. 8/9. 



312 



PRACTICAL WIRELESS 



August, 1964 



Brand new individually «xwo «■ 

... * I KT« 5/( 

checked and guaranteed 

VALVES 



ACHL 4/8 
ACP4 6/- 
ACtfPEV" 61- 



AU5Q 
ARS 
ARP 

AKP3 

ARP12 

AHP2 L 

ARP-24 

AKP34 

ARTP1 

ATP4 

ATP7 

AU7 



i-!s;, 



B2134 
BTI9 
RT35 
BT45 150/ 
BTS3 35/ 



UL9fi 5/8 
DLS19 15/- 
niJSlO 8/. 



CC3L 
010 

LT.33 

1 V77 
CV102 

(tyios 
CV40U 

CV4015 
CV4035 ioy- 
CY4046 40/- 
CY31 5/B 
I>1 1/8 

D41 3/3 

MI 6/- 

t»77 3/3 

DA30 IS/8 
DAW 75/- 
DAF96 6/- 
DD41 4/- 
E1ET5 8/- 
DET20 21- 
DET25 15/- 
DF73 5/- 
DF91 8/- 
DF92 3/- 
BF96 B/- 

DK9S- 8/e 

DK9S " 6/6 

DIM 61- 

BL93 6/- 

DM4 8/- 



23/- 

2/6 

9/- 

50/- 

30/- 

12/6 

1/- 

7/. 



El 148 
El 232 

EliiW 
E1415 

fii:24 

EA.10 
EA73 

BABC90 5/- 
EAC31 3/6 
EAt'42 8/- 
EB34 1/8 
EB91 
KBCM 

mi 4i 

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t-: n f id 

EBF89 

ECS'2 



ecs,:; 

BOTO 

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801 E I 

Ki t" -2 
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.;i $0 

torn 

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60S 
NIB 

erst; 
bivqx 

*1F6G 

sFga 

8F12 
HFL3 
8789 
6F33 



S; 

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M 
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J 7-26 

6064 

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0001 

ill Ml".' 

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90(14 



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21- 

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Valves 
ACT* £8 
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i3/10/0 
1B24 25/- 
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£37/10/0 
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Trantutors 

ocae 12/6 



MAST OTHERS IX STOCK include Cathode Say Tube* and Spttial Valett. All U.K. orders below £1 P.i P. 1/-; 

(J.O.D. 2/6 extra. Orersea* PoFtage extra at coet. 



Orders over £1 2/-; over £3. 



OC44 

Oct* 

OC7-2 
OC81 
OC82 
P. &. P. froe 



MARCONI COMMUNICATION 
RECEIVERS. CR '50. frequency 

coverage 2-60 Mc/s in 5 bauds. Two IFs. 
1st 1,600 kc.'s, 2nd 463 kc/s. Image signal 
protecting over 40 dB up to 30 Mc/s and 
20-40 dB from 30-60 Mc/s. Self-checking 
calibration (built in calibrator). Stabilisa- 
tion of supply and temperature com- 
pensation. Electrical and mechanical 
bandspread. Metering and visual tuning 
indicator. Bandpass from 100 c/s to 10 kc/'s 
in 5 stages. Acoustic filter associated with 
100 c/s. Bandpass position for CW recep- 
tion. Facilities for diversity reception. 
Excellent checked condition, £49. Mains 
P.S.U. by P.C. Radio, £4.10.0. Carriage 30'-. 
CR. 150/2. Frequency coverage I.S-22 
Mc/s in 4 bands, all other features as in 
CR.I5. Price £35. Carriage 30/-. 
P.C, RADIO'S mains P.S.U. for 
above, 90'-. 

R.209 RECEPTION SET. A 10-valve 
high-grade superb et Receiver with facili- 
ties for receiving R/T (A.M. or F.M.) and 
CW frequency 1 Mc. s-20 Mc/s. Hermeti- 
cally sealed. Built on miniature valves and 
incorporating its own vibrator power- 
supply unit driven by a 6 v. battery (2) 
point connector included. The set pro- 
vides for reception from rod, open-wire 
or dipole aerial with built-in loudspeaker, 
or phone output. Dimensions: Length 
!2in„ width Sin., depth 9in. Weight 23 lb. 
In as new, tested and guaranteed condi- 
tion, £23,10,0, including special head- 
phone and supply leads. Carr. £1. 
ROTARY TRANSFORMER. 11.5— 
12.5 v. D.C. Input 300 v. 200 mA DC 
Output, 30'-. P. & P. 15'-. 



RECEIVER TYPE R.206. Frequency 
0,55 Mc.s to 30 Mc's in 6 bands, 100-250 v. 
A.C. or 12 v. D.C. Loudspeaker in power 
supply unit. High performance super- 
heterodyne, eleven valves including a 
separate local oscillator valve, beat 
oscillator valve and two valves (Amplifier 
and Detector) in the A. B.C. system. In 
very good condition, £20. 1 0.0, including 
power pack. Carriage and Packing 15'-. 
H.R.O. Senior. Table Model. In 
excellent, fully checked, and tested 
condition (without coils and power pack), 
£15,10,0. As above but rack mounted 
model, £14.10.0, 

Original mains power pack for H.R.O. 
110/220 v. A.C. Brand new in original 
packing, 45'-. P. & P. 4'-. 
CONNECTORS FOR TCS 
RECEIVER. TRANSMITTER AND 
REMOTE CONTROL, with original 
plugs on both ends. New £1.17.6 each. 
P. & P. 2'6. 

TRANSMITTER RECEIVER. TYPE 
68T, 3-5 Mc/s netting facilities. Low 
power consumption. Requires 150 v h.t. 
and 3 v. I.t. dry batteries. In good 
condition, 35'-. Carriage 8'-. 
CARBON INSET MICROPHONE, 
G.P.O. type, 2'6. P. & P. I '6. 



EVERSHED MEGGER CIRCUIT 
TESTER. 2 ranges to 1000 £1, 100 Q 
to 200,000 Q. With test leads, leather 
carrying case. Tested £4,19.6, P. & P. 3'6. 
AR88D RECEIVERS. Fully recondi- 
tioned, £55; rebuilt models, £35; brand 
new, £95, Carriage paid U.K. 
CHR HIGH RESISTANCE HEAD- 
PHONES. New, 16'-. P. & P. I'6. 
R.I07 COMMUNICATION RECEI- 
VER. 1.2/17 Mc/s. 9 valves. "Wide" and 
"narrow" band switch. AVC and BFO, 



P. C. RADIO LTD 

170 GOLDHAWK ROAD, W.I2 

Shepherd's Bush 4946 
Open 9-5.30 p.m. Thursday 9-1 p.m. 



with internal speaker 


, 1 00/250 


v. 


A.C. 


and 12 v. D.C. 


Meas 


; 24 x 13 


X 


17in. 


Price £13.10.0. C 


arriage 20'-. 






PANEL METERS (roun 


dl 




0-20 microamps 


24* 


D.C. 




79'- 


0-50 microamps 


3* 


D.C. 




45'- 


O-S0 microamps 


IV 


D.C.** 




40'- 


0-100 microamps 


2" 


D.C. 
D.C.** 




35'- 


0-100 microamps 


2" 


35'- 


0-200 microamps 


2" 


D.C. 




32'6 


0-500 microamps 


2" 


D.C. 




21'- 


0-500 microamps 


2V 


D.C. 




30'- 


0-t mA* 


2* 


D.C. 




ly'6 


0-1 mA 


3" 


D.C. 




35'- 


0-1 mA 


3" 


D.C." 




35'- 


0-5 mA 


3" 


D.C. 




45'- 


150-0-1,500 mA 


3* 


D.C. 




29'- 


0-15 v. 


2" 


A.C. 




I7'6 


0-50 v. 


2f 


D.C. 




28'- 


0-ISOv. 


IV 


A.C. 




24'- 


0-500 v. (shunt) 


IV 


D.C. 




20'- 


0-SkV 


r 


electrostatic 


85'- 


0-10 kV 


2V 


D.C. 




63'- 


Freq. S0-70 c Sec 


I25v 


33' 




52'- 



'"Weston", as usually used also in H.R.O. 
as "S" meter. **Pro(ection type. 



PRACTICAL WIRELESS 



$f£ML fUMH&Eh 



T HANSISTOfi, SEo 

LIGHT. 

WEIGHT 



OPERATE YOUR OWN T.V. STATION! 



N.E.V. CLOSED-CIRCUIT 

T.V. CAMERAS 



Assembled and Ready 
for Immediate Use 
(Not a Kit!) 







A Once in a 
Lifetime Bargain 
— Never to be 
Repeated! 



New — may need slight adjustment. 4P5 line for operating 
on your o-aij u-Itvisicvt set. on any channel from 1 to 3. 
UIO-240 volt AX., SO-SO cycle. 

Usual price £79. Limited quantity to clear 
at the ridiculously loir price oJ only — 



£31.10 



(Out. and Ine- 84>. 



Complete irith E.M.L "M" Orade 
Vidrcon Tube, Instructions and circuitry 
Ftinpned. 

Lenses available as advertised opposite. These cameras are 
highly recommended for experimental purposes and enthusiasts, 
security and borne entertainment. 

Thousand and one application* 



2-Wave-Band 6-Transistor 

POCKET RADIOS 



\' < "■ * <■ 



lyong.modmLu wave. Gels &ji 

the at,atii.iufi fcrxi want; Light, 

Home, Lizxemboiirg, Cout*- 

QeDtdU, etc* Sot much larger 

than a packet of ctgStetLe^ 

yet giving tlie volume an 1 

tone of a radio twice its size. 

^Siui.kl bsD at 7± giu!. our 

pl-ifiij direct 

from docks to 

you ONLY . . '"" / " p.^p, 6/6. 

Complete with batteries and leather carry-as case, 

— — — — _ Ider-J for boJ-d.'iys, tjichRv*. garden, b&cktde and In the car* 



!v§jpw»l 



89/6 "Ukl 

/ p. & p. Bffl. ^^^*BJ^ 



Aj nationally advertised— 
THE HIGHLS SUCCESSFUL 

NEW 'CYCLOP' MK. Ill 

TRANSISTORISED CLOSED-CIRCUIT 

TELEVISION CAMERA 

Itnaglt-c ! Vi«w mund corners, throngh walls, and into dangerous 

■Jbtt places. InnlUaWa for mis-- industrial instroctfon. 

I MMtl olWUIIilkiD. 

Su.'ullr., i'U. \ 

I,, :t,->i, "Hit V<**w. 

nr. atTaohin.: 
direct lv into your awn 

lent picture qualitc. 
ONLY 



£68.10 



or S17.8 lie pom and 

IS urn merits nr 93J3. 

'Avi liable as be 




Full details on recfueaL 




JAPANESE! 
COSMICAR* V 
TELEVISION LENS 



•Click-stop" Aperture F/I.9 to F/2£. 4 ele- 
Aportore F/1.9 varying to F122. 4 ele- 
ment lens construction, C Mount fitting. 
Full focusing adjustment from infinity 
to h J4*. mourned leases complete »i!!i k-n.- caps and finished in an 
attractive Ijlw* and stainless alloy, at the __ . _ , 

ridiculously km price oJ uulv £ O Inn 

P. JSp.n/8. •"'•■W.M 
Also ideal (or IB mm. Movie Cameras. 



SUPER 'DAUMEYER' 
1 F/1.9 LENSES 




Designed for T.V. Wnrfc, atnl an! 

able for 10 mm. Cine Cameras. 4 clement 

lens construction, (ully bloomed. Focusing from Infinity to 24*. Standard 

C mount thread. Aperture chmlng down lo F;1B, •» ■ ■ • /* 

guaranteed brand Sew. formally retailing at j£ | , | U p. * p. S/6 



il8.12.fl, 



Our I'M. ONX,1 




TWO-WAY RADIO-TELEPHONE 

'TRANSCEIVERS' 

88-8 Mi"e Crystal cotttroTled B Fnwftrtnr. volume 
witrtrol, etc. Range apprc-i. n.n m iic lu city — 9 B 
saa and country* With smart leather caw. standanl 
pencil batteries, etc. Ready luweiuL-Jtid lor urn. 
Limited quota. Usually &1 A I g\ 
45 guineas. OUR PRICK fc,J*|s I Up 



Pper pair. 



l/< 



1 should be obtained far use in UK. 



STOP PRESS! 
MINIATURE 2-WAY F.B.I. 

TRANSCEIVERS 



Appro!. IDO-flOO } 
1 per pal 



S7 Mi/" Cttben* a»nd 
range, Limlteil -WncJl 

iKaslly Perth dnuhfc). J ■»•»"•■ «*'P. * p. 5 
{Licence should be obtained for use ir, t" k 



■ -.-. 



£9.15; 



Demonstrations of Closed-Circuit Cameras always available at our new city showrooms in 
Birmingham. Full range of Hi-Fi Stereo Tape and Disc equipment, 

ORNTONS ELECTRONICS 




LOMBARD HOUSE, GT. CHARLES ST., ( «•» «> iy Anwk.n Airw.,, ) BIRMINGHAM 3 







314 



PRACTICAL WIRELESS 



August 1964 



THE TRIPLETONE HI-FI MAJOR 

PRICE ONLY £15.18.9 COMPLETE 
Guaranteed 12 Months. 




,r>: 



A 12 -watt quality amplifier incorporatin; 
feedback, with a pre-amp for nik. an. J pi* 
mle./gram mixing* Frequency response 
18-20,009 e;s. Distortion only 0. 15 °„, with noise 
and hum —SO <1B, Separate Bass, Middle and 
Treble lift controls. Valve line-up, 12 AX 7 12AX7, 
EL84, ELS4 and BZ8I, Push-pull output with 
matching to 3 or 15 O . Fully isolate! i power supply 
from 200/250 v. A.C. input, 'with take-oil ior tuner 
etc. Size 12i^s Sin. high. 
De Luxe Case: 1-tin, x Sin, s 7; in,. 30/- extra. 



New R.C.S. VALVES 90-day Guarantee 



IT4 

3S4 

3Y4 

SU4 

,YY3 

SZ4 

SAMS 

SATS 

6BA8 

*BES 

6B~Wu 

«HS 

B.TD 

6J6 

SJ7G 

RK8 

8K7G 

8e?g 

6>'7M 



6Q7G 

mt" 

8Y6U 

BX4 

«:. 

12AT7 

12AC7 

ISA'S 7 

12X7 

X8X8 

12Q7 

25Y5G 

3516 

3-5Z4 

954 

DAF96 

r>F9« 

DK9S 
BL96 
EABCSO 5/- 
EB91 4/. 



KBi 4 i 


BJ. 


I't'LM 


w 


E BOB 1 


,-,.'- 


PES I 


;<i; 


EBFSO 


5/- 


PLHH 


Bf 


ECH42 


W- 


PYS0 


7/ 


ECH*il 


M. 


i-v-i 


s; 


Et^LSO 


M- 


pvsa 


W 




10/. 


srsi 


u 


EFLS.i 


w- 


I 22 


w 


KF184 


w. 


DBOQ 


17 


EFS8 


10 1- 


CBC81 


.■if 


EFS9 
F.I. 44 
EY51 




UBE59 
i CH81 




KXS8 


9/- 


(7CLS2 


10/ 


EZ40 


H- 


PF89 


M 


EZ80 


;.'- 


I 1.41 


e< 


EZ-I 


rf. 


FIJI 


M 


Ml" 14 




L 783 


7/ 


FC97 


7/- 


I i.y 


» 


PCC34 


B> 


YR130 


W 


FCFS0 


5,'- 


Wfll 


BJ 



I.F. TRANSFORMERS 7/6 pair 
465 E/i Slug Tuning Miniature Can, 2 x 1 i lis. 
High Q and good bandwidth. Data sheets. 



1/J50V 


Sl- 


2/350V 


2/3 


4/4S0V 


2/3 


s;450T 


2/3 


16/450V 


3/- 


32/450 V 


3/5 


25; 25 V 


1/8 


9$/SW 


8/- 


50/25V 


21- 
2/- 



5/6 



50/350V 
100; 23 V 
250/25V 

soon 2 v 
i.ooo,' t»v 

j.OOii BV 
8 + 8/450 V 
8 * 18; 430 V 3/B 
16 + 16/450V 4/3 
50/SOV 2/-'32 + 32,i350Y 4/8 



8. '800V 
16,430V 
IE BfJOV 

16-l-l6j300Y 

30 4i=.('Y 

32 -32; 350 V 



5/- 32-32MjfiY 



M. 

12.'- 
7/6 
C/6 

5/- 



■J.'6 



33+88 -j- 32/850 V7/» 
50 + 501350V 71- 

64 + 120/ 350 V 11/ 6 

100 -200 /275 V 12/8 



TELESCOPIC CHROME AERIALS, 12 u ;3iin., a/a. 
TRIPLEXERS Bands I, II, III, 12/6. COAX PLUG, 1/-, 
LEAD SOCKET, 21-. PANEL SOCKETS, 1/-. ' 
OUTLET BOXES (Surface or iiusht, 4/- oa. 
BALANCED TWIN FEEDER yd. 6d. SO or 300 ohms. 
TWIN SCREENED per yd. 1/-. SO ohms only. 
Wirewound Est, Speaker Control, 1.0 n 3/-. 25 o 8/8. 
WIRE -WOUND POTS. 3 WATT. Pre -set Mln. 
TV Types. All Faluns to 18 ohms to 25 K., 3/- ea. 
30 K., 4/-. (Carbon 30 K to •> meg., 3/-». 
WIRE-WOUND 4 WATTS Pots. Long spindle. 
Value, 30 ohms to 50 K., 8/6: 100 K., 7/8. 
PHILIPS TRIMMERS. 0-10 pF.. 3-30 pF., l/». 
TRIMMERS. Ceramic. 30, 50, 70 jiF„ 94.; 100 pF„ 
100 pF., 1/3; 250 pF., 1/6; 50(1 pF.. 700 pF., l/». 
TV etc. TRIMMER, 1000 pF., with knob, 2/-, 
BESISTORS. Preferred values, 10 ohms to 10 meg., 
i w., 4uL; I w„ 4d,: t w., 6d.; 1! w., 8d,; '-' w., 1/-. 
High Stability, f w., 1%, 2/.. Preierreii values 
TOO to 10 meg. Ditto S% 10 n t» 22 meg., at 
BRIMISTOSS. CZ1, 3/6: CZ-2. 2/6; CK3. 1/8. 

in Stf I WIRE-WOTJND RESISTORS J !P 

15 vStt J 10 *"*-»« -^ 1 1f: 

12.3 K to 23 K 10 w , . . 3/- 

Toggle Switches, s.p., g/-; d.p„ 3/U 
fl,p.d.t., 4/-. Min. Slide d.p.d.v,., 3/6. 



Volume Controls 

Linear of 1,og Traoki 
Long spindles. Midge. 
5 K ohms to 2 Aleg. 
L.S. 3/-; D.P., 4/8; 
Stereo L.S 10/6: D. P. 14/6 
Lm, log + lm» A log, 7/8 



80 



ohm 
CABLE 
Semi-air spaced 
40 vds. 17/6 
80 yds. S57- 



COAX 



6d.yd. 



Ideal 623 lines. 
Low loss 5-iB 



A.C. 



MAINS TRANSFORMERS 280/258 

■Po#lap* 2/. each trfjtwfQ.mcT. 
STANDARD, 250-0-230, 80mA. 6.3 v. 3.5 a, 
tapped 4 v. 4 a. Rcctlner ti.^i v. I a.. 5 v, 
2 a. or 4 v, 2 a., 22/6, ditto. ;iSO-0-34O 
MINIATURE 200 v. 20 mA. fl.3 v. 1 a. 
MIDGET. 290 v. 4i mA >i.:i ... 2a 
SMALL, 230-0-2:60. 4u mA, 0.3 v, 2a. 
STD. 2 ,10.0-250, ils ihA, (1.3 v . 3.S *, 

HEATER TRANS. 0.3 v. 1| a 

lilltn, tapped 1.4, 2, 3. 4. 3, li.3 v. 

Ditto, MC 8.3 v. 4 amp 

GENERAL PURPOSE LOW VOLTAGE, 2 amp. 
3, 4, 3, 6, t>, o, 10, 12, 15, 18, 24 30 v. . , £2/9 
ADTO TRANSFORMERS. I. "V->, 22/6 

(i, 115, 200, 230, 250 v. flOO w 82/6 

MULLARD "510" Mains Traailormer . 33 IS 
MAINS POWER PACKS. Keady Uulit with 
''I'raiihfonuers. RcctittBK, t'oliduUfBrs, pliividlns 
M.T. and L.T. outputs, 

200 v. 20 ma. I'>.!\ 113; v. 1 a. II. II. ,. 26/8 
220 v. SO dm, I t.C. 0.3 v. 2a. A3 '. . . 35/8 
250 v. 10 mm. D.V. 6,3 v. 3.0 a. A.C. . . 4S/6 



29;8 
10/6 
15/8 
17/8 
17/6 
7/8 
S/8 
10/6 



INTEk VALVE rRANSFOrtiiifcJKS. 3:1 ... 5:1, 91- 

O.P. TRANSFORMERS. Heavy Duty. 6/0. Mtiin- 

ratio, 7/8. Multinitlo heniv duly puah-Pull, 10 w„ 

15/fl. Fisttfrj, 4/6. Hub. mlo„ B/«. 

10w. O.P, matching trans., 3, 7. 15 0. 12/8. 

L.F. CHOKES I.VIOII.. 60/615 mA, 5/-: 1011. SB mA, 

10/6. Mill. 150 m4. 14/-. 



( ,-s.l. IHHtSICK TIl.WSumtll.KS 
lor hoatei* cathode short circuit, or 
tubes with InlJIiisr cml.sslnn, full 
instruction* s-uppJled, itibIiis Input. 
I'ypc A it|>flnnnl 35 "„ nnrl SIT., lionsl 
Ii. nr 4\. nr 6.SV. i)r Hl.iiv. itr li.Bv. 
Stale tollap;c rciiuircri. I'RH'K 10/fl. 



TINNED COPPER WIRE iti to -'-' «.w s „ hi... 3/.. 
ENAMEL COPPER WIRE 10-':2, 2/9; -Jl-Su. S/6; 
32-40. 4/8; D.c.f. 28, 34, tt fwg, 2oj.. 3/6. 
FULL WAVE BRIDGE SELENIUM RECTIFIER: 
ft, 8 or 12 v.. 1! amp.. 8/B; 9 a.. 11/6; 4 a.. 17/6, 
CHARGES TRANSFORMERS, Tapped input 200- 
2J0 r, for thargiug at 2, 6 or 12 v.. I J amps., 16/8; 
J ami!.-., 17/6 r 4 amp?.. 221%. <in-uit Included. 
4 AMP CAR BATTERY CHARGER wHh auk 
rnrter. \.fmif, lute 1 «-<-. . t... i,,t 1; v. or 12 v.. 69/6. 



BOOKS list S.A.E. 
toys' Book of Crystal Sets. . .. 2/6 
•WAV," Kntllo Valve Data .. 7/6 

liiirli l-'ldclitj Sticukt-r Knrlosure 5/- 
Valtc ami T\~ 'l'uhe Ktiuivalcnts .. 0/6 

TV Fault Finding 5/- 

Mulltiril AjiiiilitliT MiimiHl .. 8/6 

Hud it> Valvt> buide. Books 1, 2, 3. 

4 or 5 5/- each 

Practical Itaditi Inside out ,. 3/6 

Maxtor Colour C'odr Chan .. 1/6 

Transistor Controlled Models -- 7/6 

ItitiTiiiUHiiiiil Kuilin 'siiilitiiis ., 2'6 



4 TRANSISTOR PUSH-PULL 
.AUDIO AMPLIFIER 

A ready bulli iiiiiilaiiu-e push-puli amplitier with 
l»nver ami output tranaiormers, 4 transiator^. 
Ideal ior use with retiord ulavers, tBtdOOBOa., 
BABY ALARMS, etc. Complete with full 

M"] It* Instructions and circuit. 
Price *»l / V iiy. Halt, 2.-:i. 2lin, Speaker 15/-. 



1964 RADIOGRAM CHASSIS 




THREE WAVEBANDS FIVE VALVES 

B.W, 16 ro — 30 m. LATEST MILLARD 

M.n. 200o).— «B0 ni. BQSS1, EF80. EBC81, 
l. w , soo iu. —2,otio m . i-: i ,8-t , \-;y.y-i 

12-month Goarantee. 
A.l'\ 2flfl'250 v. Short-Mctliurn, l^ng'iiratu. 
I'errltii Aerial A.v c :; .,i,n, ..utpul, S watt*. 
Tape Sockets. Gbus dial, horizontal n-onlinir, 
:i. v Tin. Allgiit'd aud ealibraietl. [nlated 
Chassis- size I3ilji. x 7lu. high x 5 'in. deep. 

£9.15.6 <■'•«■■ * tu*- 4 ■■■ 



BAKERS 

'Selhurst* 
—RADIO— 

THE 

CONNOISSEUR'S 

CHOICE 



none genuine 
without this seal' 




12in. STALWART HEAVY DUTY ISw, 5 Ens. 



46-13,000 cps. k, or 15 ohm voice coils. Unlimited 

Applications. Fiat response 100 10 10,003 op;. 

magnet, 12.000 lines. Price tor t,uaiity unDeai- 

ahie. 

Lain^TANDARD HEAVY DUTY 20w, 7 Kns. 

More powerful magnet 14,000 dnes special sus- 
pension. 40-14,500 cps. Recommended when- 
ever a high standard o! reproiiuction is if siren 



12in. BASS HEAVY DU7Y 25w. 



12 KM, 



New 1964 high Power moaei. Aluminium cojI 
former with magnetic damomg ^5-13.000 apt 
Ideal for ail electric guitars. 
15in. AUDITORIUM MODEL 35w. IS Ens 

Improved magnet a.coms^. Vitb heavy p.sled 
sleel piates, weight 18 its. 17,000 lines, k0- 
12,000 cps. Solid heat proolea Paxoiin Coil 
Former, Ideal Electric Gnitsrs. 



LOUDSPEAKERS P.M. S OHM. 21. 3 4, Sin.; 

7 i 4tn., 15/6; olin. Rota, 16/6; Sin. Ples=rv. 17/6; 

9 i 6in., 8 x 5m.. 21/-; 10 5 Bin.. 22/6; 10 in. Eoia, 
30/-; 12Tn. K.A.. 30/-; EMI, Double tone Ceramic 
magnet 10 *. 13 x 5m.. 45/-. i.om t'weecr 29 O 

STENTORIAN HF1012L Umi. : tn 15 ,-,hms, 10w. 
92/-; «in. HFS12. 76/-; > mmawi CX3U00. 33/-, 
EXTENSION SPEAKER iABIKET. iiin., 15/6; 
6iiu.. 16/6; Sin. lil/fl; loin. 29/6; 12in., 60/-. 

TWIN GANG TUNING CONDENSERS. 365 pF., 
miniature lin. i l|in. i IJin.. 10/-; 500 pF Standard 
with trimmers, 8/-; midget, 7/8; with trimmers. 9/-. 
500 pF slow motion tuning, standard B/-_ Trai^-i.-tor 
gang 20S + 178 pF with trimmers, 10/6. SMALL 

3 gauK SOO pF, 17/-. SINGLE 365 pJP, 7/6. SINGLE 

10 pF, 25 pF, SO pF, 75 pF. 100 pF, 150 pF, 6/6. 
Boiid dieleetric 100, S00, 500 pF. 3/6. 

CONDENSERS. New stock, 0.001 mfd. 7 fcV. 
T.C.t'.. 6/8; Ditto, 20 fcV. 9/6; 0.1 mfd.. 7 fcV, 9/6; 
Tubular 500 v. O.001 to 0.05 mfd., 94; 0.1, 1- 
0.25. 1/6; 0.5/350v_, 1/9; 0.1. 3301 -. Ed.; 0.01 2 U00V. 
O.l.l.MOv.. 1/B; tf.l mfd. -,=,000 volts, u/o. 
CERAMIC CGNDS. 500 v. n.3 pF to 0.01 mfd., 9d. 

SILVER MICA CONDENSERS, 10% 5 pF to 500 pF, 
9d,; BOO pF to 3,000 pF, 1/-. Close tolerance 
(+i pF) 2.2 pF to 47 pF, 1/-. Ditto 1% to 50 pF 
to S15 pF. 1/-; 1,000 pF to 5.000 pF. 1/9. 

WAVECHANGE SWITCHES 

8 p. 4-way 2 wafer long spindle , , , . 6/6 

2 p. 2-way or 2 p. fi-way ion 5 spindle . . 3/6 

4 p. 2-way or 4 p. 3-way long spindle . , 3/6 

3 p. 4-way or 1 p. 12-way long spindle . . 3/6 

Wuvechunse "MAKITS". Wafers avail- 
able: 1 p. 12 way, 2 p. 6 way, 3 p. 4 way, 

4 p. 3 way, 6 p. 2 way, 1 wafer switch. 8/6. 
2 wafer switch, 12/6: 3 -.vai'er switch. 16/-: 
additional wafers up to 12, 3/6 each extra. 

Valveliolders. EA50, 6d, B12A. CRT, 1/3- 
Engl. and Amsr. 4, 5 ana 7 pin, 1/-. 
MOULDED Mazda and int. oct., 6d.; B7G, 
B8A. B8G. B9A, 9(1. B7G with can. 1/6. B9A 
with can. 1/9. Ceramic EF50, B7G, B9A, 
int. oet.. 1/-. B7G. B9A cans. 1/- each. Valve 
plug-s B7G, B9A, int. octal, 8/3, 



high iiAi^ iv i'iu;-A.Mi'Liin:its 

B.B.C. Channel 1 lo 5. Gain lBdB. 
ECC84 valve. Kit price S8/6 or 4K/6 
with power pack. Details 6d. (PCC84 
valves if prelerred). Coils only 9/6. 

BAND III I.T.A.— Same prices 
Tunable channels 3 to 13. Gain I7dB. 
Circuit and coils only. 9/6. Chassis 4/9- 



THE ORIGINAL 



RADIO COMPONENT 



Our written naraatea with every purchase 



i.ow loss lib 4 I...J , liur written c;uaranlt-t- ivltrt •■ 
100ft. 50f M. sl/OyO. Mil (OMrOMM IN 1/-. 



OfES ALL DAY 
i\\ ed. 1 p.m.l 



August, 1964 



PRACTICAL WIRELESS 



315 



THE "INSTANT" BULK TAPE 

ERASER AND RECORDING HEAD 

DEMAGNETISER ,*)W»v.A.i:. 




PLASTIC RECORDING TAPE 

Double Plsy i in. reel, 2.400ft. 42/- \ Spare 
flln. reel, l.'inwi. Z51 - , plastic 

Long Pliy 7in, reel, l*iwt. 22/8 , ru R,eels 
5J1d. reel, l.'iuoit. 17/8 .Inn. 1/6 
Sio. reel, SW>i"t. IS/8 ^ 4in. 2/- 

— 51 n. £/- 

Standard Tin. reel. l.'JPClt. 17/fl 5||n 21- 

5lo. reel. BQflU. U/6 7in.' 8/6 

"EAS1SPLICE" Tape Splicer 5/- 
Leader tape 4/6: Splicln? tape 3/-. 



MAHTIX TAPE PIU-AMPl.ll-ll-.RS 

& DECKS > I'l.AY-UACK THROUGH 

VOIR OWSi AMPLIFIER) 

Collaro i truck i Coilaro st udln 
I'ri-ajiifi, ta.B.O : I ape deck £10.15.0 

COMPLETE RECORDING & PLAY- 
BACK AMPLIFIERS 

Collars ampll >cr £11.11.0 



MAINS DROPPEBo. ,M„1gei adluntiibte sliders 
11. 3 A. I.IKHI (ihtiin, 8/-. II.-.' A, I .Jul) dllllH, »/- ; 
O.loA, I,.. B.JA, i,l»00 ohms. 6/-- 

MIKE TRANSFORMERS, .nil, 3/9. 
P.V.C. Covered Wire. stagi* or stranded, 2d. yd. 
SleBvinit, 1 or - nun. 2d.; 4 mm.. 3d.; »> mm,. Bd. yd. 
SPEAKER-FRET. OokL Hnioon .ir tireeo Cloth 
17 x 201ti., 5/-. W x ssni., 10/.. Tygan various colour* 
lata, iriile Fran 10/- K.I 281a. wide from 8/- tL 
ttamiilm li- .i.l, I 'J i lUin., 8/-, 

Panel mounting fuse holder. 2/-. Fwbj Um. SObA- 
SA. 6d. liwuiateil side tuners. 3/6. Blh BtdVptr. 3/8. 



CRYSTAL SET BOOKLET. l/>. 

CRYSTAL DIODE B.E.C. 2/-. GEX34. 3/-. OA81. 8/-. 
HIGH «E3. PHONES. 4,000 ohms. IS/-. -'.tHJi* ohms ' 
12/8. MOVING COIL PHONES. KXI ohm*. 10/- 
5WITCB CLEANER, Fluid squirt upout, 4/3 tin,' | 



"6 + 1" TRANSISTOR RADIO 

First class components to make a 8 
transistor 2 waveband Buperhet chassis. 
Ideal for portable or table radio. All 
Farts including BVA transistors, fernte 
aerial, ti:ilh car aerial coil, printed 
circuit. Blln. x 2tir... but EXCLUDING 
Speaker and cabinet. c a c n 

Speakers, 35 ohms. 7 x din.. 2l/.»*»-0-U 
Bin.. 17/6: 3lin., 15/8. Cabinet 27/6. 



BULG1H PLDQS AND SOCKETS. Non-reversible ' 
P74. U-pin, 4/S; P73, 3- pin, 4/6; PI 94. 6-pin, 6/6 
JACKS. English open circuit;. 2/8. Owed circuit, 
4/5. finintlie type 3-pin. 1/3. Grun.Jig lead jack 8/8. I 
JACK PLUGS. English, 3/-; Screened. 4/.; GrucdiH. 
3-pin 3/8; Phono Plug*. 1/-; Sockets, Bd. 
ALADDIN FORMERS and cores. 1 in- Bd.; Iln„ KM. 
O.Sin. FORMERS, 9937 or S cans TV1 or 2, Jin. 
fo. x 2 tin., or tin. sq. z liin., 2/- with cons. 
SLOW MOTION DRIVES. 8:1, 4/3; 3fi:l, 10/8, 
SOLON IRON, 23W, 200V or 280V. 24/-. 
AH TEX SOB-MIH. IRON. 15 w, 200 or 240t., 29/6. 
BENCH STAND for above, 12/6. Spares in Stock. 
Paxolin Panels, 10 x 8 x Vuin,. 2/-. 
Miniature Contact Colled Rectifiers, 
250V. 60mA, 7/6; 250V, 85mA. 9/6. Selenium 
RecL, 300V 85mA, 5/-. K3/25, 600V, 5mA. S/-. 
RM4, RM5, 14A100. 14AU6, 10/- each. FC31, 
20/-. TV etc. Silicon Suh-Mtn, Rf ctlflers, 
250V 450mA. 10/-: 250V 150mA. 5/6. 



465 ke/s. SIGNAL GENERATOR 
Price 10/6, ready made with valve 1S5. 
POCKET SIZE 2!x4}xlln. One resistor 
to change, full instructions supplied. 
Battery 8/6 extra. Details Free. 



Coils We&rite- "P" Type. 4/- each. 

Osmor Mldjret "Q" type, adj. dust core, 

from 4/- each. All ranges, List S.A.E, 

Repanco DRRt L. and Med. T.R.F. 

with reaction, 4/6. Med. wave D.R., 3/6. 

Ferrite Aerials, M.. 8/9; M. and L., 12/6, 

Osmor Ferrite Rod Aerials, L. and M. 

for translator dre site, 10/- each. 

Ferrite Rods, 8 x Sin., rj x lin,. 6 x '/i,ln„ a/-. 

R.F. Cokes, 8/6. Osmor QC1, 6/9. 

T.R.F. Coil«, A/HF. II- pair; HAX, 8/6. 

Screwdriver, oin., 6d. Test Prods, 2/B ea. 

Ncoslde TrliruninK Tool, 1/fi. 

Neon Mains Tester screwdriver, 5/-, 

Multlcore Solder, 4d. yd. Dispenser, S/6. 



Blank Aluminium Chassis, 13 s.w.b. 
i sides, riveted corners, lattice fixing 
holes, 21 In. sides, 7 x 4in.. 4/6; 9 x 7in, 
5/9; 11 x Tin.. 6/9; 13 x 91n., 8/6: 14 x llin. 
10/8: 15 x 141n., 12/6. 
Aluminium Panels, 13 s.w.g., IS x 12!n.. 
476; 14 x 9in„ 4/-; 12 x Bin.. 3/-; 10 x 7in„ 
2/3; 8 x 6tn., 2/-; 6 x 41n., 1/6. 



RADIO AND TELEVISION SPARES 

Ml IfiidinR makes, volume t-ontrolH, 
etc.. line nut nut transformers, etc., 
B. V, A. valves irum-nt and obsolete 
tyiies). Send S.A.i;, for quotation. 



WEYRAD 

COILS AND TKANSJ ORMER8 FOR 

a-ii'.-wi-: 6-nt ansistoh i-itiMF.it 

tllttin AND FKRKITE AEUIA1.. 

Long and Medium aerial — RA2W 61a. rod 
203 pF tuning, with car earlal coll. 12/6 
Osc. Coil P50/1AC 17S l>F tuning 5/4 

1st and 2nd I.F. P60/2CC. 470kc78 l!/16in. 
dla. by Jin. 5/7 each 

3rd I.F. P50/3CC 6/- 

spare Cores 6<l. 

Driver Transformer— I,FDT4 9/8 

Wavechange Slide Switch d.p.d.t. 3/6 
Printed Circuit— PCA1. Size 21 x 8|in. 
Ready drilled and printed 9/6 

Volume Control. 5K-DP 4/8 

35 ohm Speakers, 3{in., 15/6; 51n., 17/6; 
7x4in.. 8U-. 

Tuning Gang with trimmers 10/6 

6 Mullard Transistors and diode 42/6 
Constructor's Booklet 2/- 

3 ohm OJ, Trans. O.P.T.l 10/fl 

NEW MILLARD TRANSISTORS 
OC71 8/-, OCT2 7/6, OC81D 7/8, OC81 7/6, 
DC448/-. OC45 8/-, 0C171 10/6, AF11" fl/6. 
Sub Miniature Condensers. 0.1 mFd, 
30v.. 1/3. 1, S, 4, 5, 3. 16, 25, 30. 50. 100 mFd. 
15 voit, 2/6 ea. Translator Holders. 1/3 . 

SINCLAIR "SI.1M1.INE" RADIO 

Med. wave kit. 2 transistors, 2 diodes, 
earphone, ferrite aerial. Cabinet 
3 x II * lin, 48/6, batt. 3/6. 



THE "POWER MITE" 45/- 

PM9 Mains Lnlt 9 volt for Transistor 
Radios. Same size as P.P. 9 (2O0/250V. 
A.C.). 



ADASTRA 3-3 AMPLIFIER 3 WATTS 
HIGH FIDELITY AT LOW COST 




BUILD YOUR OWN 
RECORD PLAYER 
FROM £9.19,6 

AND 

SAVE 

POUNDS!! 



4 Speed Autochanerer orSlnple Player 
units with Brand New 2-tone de luxe 
t nlimeiT. I : x is x K j In. Strong handle, 
gilt inn -it clips and hinges. I'sed oy 
I Hiiiims Hake fur jkku-. models. 
Ready cutout motor tioard Uxl.tin. 
Front tmftii. wilh 1 x 4in. high flux 
loudspeaker and 3 watt i valve CV85, 
WHS nniplilicr huill on metal chassis 
I,' \ l \ -'lin. tluality 3 ohm nut put 
transformer, hiw hum level circuit. 
Volume and Tone controls. 3-core 
safetj mains lead. All Items tit to- 
Kt'ther perfectly. Special instruc- 
tluit- en:ii>le ;i-.«.emlil> in 30 minutes, 
onl> 5 wires to join! 13-mouth written 
miariiolee. Avallahle separately or 
[iitckiisr deals ns lielnw. 
AUTOCHANGER KITS COMPLETE (M «bnTe» 
B.S.R. Mousroh . . . . ill.10.0 P.P. 5 « 
Gsmri Auto»l;m . . £12.18.0 P.P. ,V« 

SINGLE PLAYER KITS, Complete <as above) 

E.M.I. Junior .. .. £8.18.6 P J?. I 
Garrard SRP10 . . Sll.5.0 P.P. 6/8 

OR SEPARATELY 

Cabinet with board 14 i 18m. 

cut out to vour ohoioe £3.9,6 P.P. 3/8 
Amplifier with 7 i 4tn. ipetker £3.17.8 P.P. 2/6 
AUTOCHANGERS 

B.S.R. TJA14 ., .. tt.19.8 P.P. *.'■ 

B.S.S.CAia SUmllne .. 16.17.6 P.P. 4,'8 
G*trard Autoiliin . . 16.17.6 P.P. 4/6 

(INGLE FLAYERS 

Garrard SEP10 . . , , 15.5.0 P.P. */» 

E.M.I, auto itop/itart . . 15.S.0 P.P. *i9 
LM.I. Junior £3.7.6 P.P. 3/6 



TRANSCRIPTION UNITS 

Garrard 4HF .. .. §15.15.0 P.P. 6/- 

Pbilipa AG101B . . , . 112.5.0 P.P. 5f- 

Girrwd AT« . . . . 110.10.0 P.P. 5/- 



SARGAtK XTAL PICK-UP ARM 
Complete with ACOS LP-78 Turnover Head. 20/- 

Replflcement sapphire Jtjli 5/-, diamond 16/-. 
Mono GPS9 Xtab 15/-: Swrw Ronnette 80/-. 



BARGAIN SINGLE PLAYER KIT 200/650 v. A.C. 

£5.15.0 mat a. ! ,B " """"*' 

With II lllllll Amplifier; 8 watt; 2 valvei. OCL62. 
UYSS; Hich-Bui bin. ipeaaer; 4-tpeed E.M.I. 
Tarntablt. 16, 33, 45 78 r.p.m.; Cryital Plek-np 
tor LP/STD. Reeordi, 71n., IDux, IBia.; Cat out 
HountiOE boards 12 J x 9iin. 




ARDENTE TRANSISTOR TRANSFOEMHRS 
DS035, 7.3 CT:1 Puih-Pull to 3 ohma lor OC72. 11/- 
D3034. 1.74:1 C.T. Puab-Pull Driver lor 0072, 11/- 
D3C68, 11.5:1 Output to 8 obml lor 0CT2. etc., 11'- 
D167. 18.2:1 Output to 3 ohmi tot 0C72, tie.. 12/- 
D239, 4.8;1 Driver, Jin. x Jiru x iin. 11/8 

D240, 6.5:1 Driver. ,in. i .in. xjio. 11/8 

ARDENTE TRANSIBTOR VOLUME CONTROLS 
VC1545, 6K with switch dia, ,6in. 6/8 

DEAF AID EARPIECE, Xtal or meiraetlo 7/8 

SUB-MIN. JACK AND PLDG ■i.B or a.5 ram 8/6 pair. 



READY BUILT, WIRED AND TESTED 
A.C, 206-250V. Valv.es ECL86 and 

EZ8B. 8 ohms output. Controls: hass, 
treble and volume, separate front panel 
with de luxe linlsh. duality ninUi- trans- 
former. Enamelled cluissls flln. x Sin. % 
31a. Price £4.19.8. Details S.A.E. 
"Performs agreeably well" (The Gramophone) 



MINIATCRE 


PANEL METERS 


Size Win. 


~ii. 1" reel si on Jewelled hear- 


InKs, a% accuracy, silvered dinls 


black 


numerals 


and 


line pointers. 


zero 


adjustment -ercw on front of 


meter. 


0-1 mA 


. 27/8 


0-50 U.A 


39/6 


0-5 mA 


. E7/6 


0-500 u. A 


. 3E/6 


0-309V 


B7/6 


"8" Meter 


. 35/- 



MOVING COIL MULTIMETER TK*8a 

0-1000 v. A.C./D.C. ohms .0-I00k. etc., 49/8. 

0-150 m 2in. scale. 



component shop 337 WHITEHORSE ROAD 
SPECIALISTS WEST CROYDON 



'P.P. charge 1/- C.O.D. 2/- extra. 
Buses is:, or 66 pass door. w. R. Station gelhunt 



Telephone: THO I66S 

\,£rporl n'slrem*. Smirl T0mUt9H 
and twtrij pottavt. Ml 



CRYSTAL MIRK INSERTS, P/8 

High output. Size llin. dla. x iin. 
ACOS MIC. 14, Insert IJln. dia. x iin.. S/6 



ACOS 3fl-t III, I.l XK STICK MIKE 35/- 

1SI, CJl Al.liY SUCK MIKE 85/- 

TELEPHON K I" A PE MIKE 10/6 

(,i It \H CONTACT MIKE 15/6 

MOVING roll. MIKE 59/6 

FLOOIt S1.VM1S. ., 57/6 



316 



PRACTICAL WIRELESS 



August, 1964 



[ 



RADIO-AMATEUR 
EDUCATIONAL 




NSTRUME 
E Q U I P M E 



NTs] 



With the cleavty-written instruction manuals* 

anyone can buittt any of these tnmteis — 
have the «■«#•/##"«* best eanipment — 40 mi save money 



HI-FI F.M. TUNER. Tuning 
range 68-108 Mcs. Tuning unit 
(FMT-4U) with 10.7 Mc.'s. 
I.F. output (£2.15.0 inc. P.T.) 
I.F. Amp. (FMA-4U) complete 
with cabinet and valves. 
(CI 3.3.0). Total kit £15.18.0 
Assembly can be arranged. 




■ 
1 

t 


- AMATEUR BANDS RECEI- > 

r ^**WBlBll«Sjg g ^i VER. Model RA-I. Covers > 

?jf Kssa=~^ : , i^BU a " Amateur Bands from 160 i 

•■'"KB 1 co ' Orn . Special features incl. 1 

1 half lattice crystal filter, 8 1 

2JP^BB^""s££ B va ' YC5 ' signal strength "5" \ 

=S!^sRt JH@ ^^r mete'-, tuned FLF. amplifier < 

~^==S5Ja^ stage. ... Kit £39.6.6 < 

^ Assembled £52.10.0 < 



5W Hl-Ft MONO AMPLIFIER. Model MA-S. A low-priced 
well designed amplifier. Printed circuit construction makes it 
■asy to build. Kit £10.19.6. Assembled £15.10.0 

STEREO CONTROL UNIT. USC-I. Luxury model with 
inputs to suit any pick-up or tuner. Kit £19.10.0 Assembled £26.10.0 
MONO CONTROL UNIT. Model UMC-I, Ideal for use 
with MA- 1 2 or similar amplifier. Kit £8.12.6. Assembled £13.12.6 
HI-FI EQUIPMENT CABINETS. Large range, in kit form 
or assembled and finished, available to meet various needs. Details 
on request, ... ... ... ... from £7.7.0 to £37.16.0 



6W DE LUXE AMPLIFIER. Model S-33H. An inexpensive 
Stereo-Mono amplifier, with high sensitivity. Suitable for Decca 
Deram Cartridge. Kit £15.17.6. Assembled £21.7.6 

6 TRANSISTOR PORTABLE. Model UXR-I. Prealigned 
I.F. transformers. Printed circuit, 7 x 4in. high flux speaker. Real 
hide case. Very easy to build ... ... ... Kit £12,11.0 

SHORTWAVE TRANSISTOR PORTABLE. Model RSW-I. 
Two short bands, trawler and medium wave Kit £19,17.6 

HI-FI A.M. F.M. TUNER. Covers F.M, 88-108 Mcs, A.M. 16-50, 
200-550, 900-2,000 m. Tuning heart (£4.13.6 inc. P.T,} and I.F. 
Amp. £21.16.6, Printed circuit board. Total ... Kit £26.10.0 




"MOHICAN" GENERAL 
COVERAGE RECEIVER 

Model GC-IU. Fully Tran- 
sistorised. Excellent portable 
or genera) purpose receiver 
for amateur or short wave 
listening. Sec Cull spec, leaflet, 
K,t £37.17.6 
Assembled £45.17.6 



"OXFORD" DE-LUXE TWO 
WAVEBAND TRANSISTOR 

PORTABLE. Model UXR-I The 
ideal domestic, car, or personal 
portable receiver. 10 Semi-con- 

ductors. Send for full details. 

£14.18.0 Kit (inc. P.T.). Assembly can 
be arranged. 




' Assembled models also available: prices on request— Deferred terms available over £10. Free delivery U.K. 

SEND FOR FREE BRITISH HEATH KIT CATALOGUE- OVER 50 MODELS TO CHOOSE FROM 



PA AMPLIFIER. Model PA-I. 50W output. 
For vocal and instrumental groups, guitars, etc. 
4 inputs, 2 speakers, Tremolo. Send for full details. 
Kit £54.15.0. Legs optional extra 1 7 '6 set. 
Assembled £74.0.0. 

SOW POWER AMPLIFIER. Model MA-50. 
Ideal for PA work etc. Kit £19.18.0. Assembled 
£27.18.0. 

K 

2*in. PORTABLE SERVICE OSCILLOSCOPE. Model OS-I. 

An ideal light, compact scope for servicing and general work. 
Printed circuit construction. Kit £21.18.0. Assembled £29.8.0 

Sin. OSCILLOSCOPE, Model IO-I2U. Wide band amplifiers 
essential for TV servicing. F.M. alignment, etc. T/B covers 10 c.'s — 
500 kc/s in 5 ranges. Kit £32.12.6. Assembled £41.10.0 

VALVE VOLTMETER. Model V-7A. Measures up to 1,500 
v. (D,C. and r.m.s.) and 4,000 pk-to-pk. Res. 0.IQ to 1,000 Mil. 
Kit £13.18.6. Assembled £19.18.6 




COMMUNICATIONS TYPE RECEIVER 
Model RG-I. An excellent low cost receiver 
Freo. cov,: 600 kc/s- 1. 5 Me/s. 1.7 Mc s-32 Mc.'s. 
A two speed tuning drive. R.F. "front end" 
supplied assembled, aligned and tested. Send 
for details. Kit £39,16.0 Assembled £53.0.0 



6W STEREO AMPLIFIER. Model S.33 3 w/ehl. Inputs for 
radio-tape-gram. Stereo/Mono, ganged controls. Sensitivity 200 mV 
Kit £13.7.6. Assembled £13.18.0 
MULTIMETER. Model MM-I U, Ranges: 0-1.5 v. co 1,500 
v. A.C. and D.C. I50|aG— ISA D.C. 0.2-^l to 20Mu. 4^ in. 50yA 
Kit £12.18.0. Assembled £18.11.6 
R.F. SIGNAL GENERATOR. Model RF-I U. Up to 100 Mc/s 
fundamental, 200 Mc/s on harmonics. Up to 100 mV output all 
bands. Kit £13.8.0. Assembled £19.18.0 




(Gee Heathkit models at the RADIO SHOW, 
STAND No. 32, EARLS COURT, LONDON, 



August 26th— September 5th 1964 



^ a - ,-,"-"„ % „ -. -,-,.". ■, * 



AMATEUR TRANSMITTER 

Model DX-40U. Self-contained. 

DX-40U 80-10 m. Power input 75 w.CW, 

60 w. peak C.C. phone. Output 

NfB w. t» aerial. Prov. for VFO Kit £33,19.0. Assembled £45.8.0 




DX-IOOU 



DAYSTROM LTD. 

Dept. P.W.8, GLOUCESTER, ENGLAND 

A member of the Davsrrom Group, manufacturers of the 
WORLD'S LARGEST-SELLING ELECTRONIC KITS 



AMATEUR TRANSMITTER. 

Model DX-I00U. Covers all 

amateur bands. 160-10 m. 150 w. 

D.C. input, self contained with 

power supply. Modulator, VFO Kit £79.10.0. Assembled £104.15.0 
*» — — -. — — _ — _ — _ — _— — — _ — -g 
| Send me FREE BRITISH CATALOGUE (Yes/No) j 
I Full details of model(s) . 



ADDRESS 



PW8 | 



.__ 



^d ' : i ? 1 1 1 f 1 1 1 r i r i n m 1 1 1 1 • 1 1 n 1 1 n ; ; 1 1 ! ■ 1 1 ■ 1 1 . i ' i i ■ i ■ i ■ « ■ i m i ■ p 1 1 m i r ■ i r 1 1 1 n 1 1 n m i . n i » 1 1 1 ' 1 1 1 r 1 1 • n i ' 1 1 1 1 m 1 1 f i n n 1 1 1 ! 1 1 1 1 ' r 1 1 ■ 1 1 r f m i r i r < n r ' m p i m n t f i n t i r l^ 



Practical Wireless 



! 



~. i J 1 1 i n I N I . I M 1 1 H : M . N I i I I I ! ! I 1 1 1 ; i i I , ! I : i , I ■ - ! ! ■ M . I ■ ' II 1 1 < / I N I M J I i I ; lu I . I i 1 1 ^ I : I 1 1 1 1 1 < T I 1 1 n I N 1 1 T I M 1 1 T I f ^ 1 1 1 1 U I P^ 



Vol. XL No. 490 AUGUST, 1964 =_ 

etWBiimnflHimwiiiiiiiiiiiiiiiiMiiiiiiinnnimiil 

Editorial and Advertisement = 

Offices: = 

PRACTICAL WIRELESS E 

= George Newnes Ltd., Tower House, = 
Southampton Street, W.C.I. = 

George Newnes Ltd., 19(4 = 

= ^^^^^^^^^^^^^^^^^^^^^ = 

E Phone: Temple Bar 4361 = 

■ Telegrams: Newnes, Rand, London. ss 
= Registered at the G.P.O. for trans- = 
= mission by Canadian Magazine Post. = 

= 3 

SUBSCRIPTION RATES 

5 including postage for one yesr 

To any part of the world £1.9.0 H 



Contents 



Editorial 317 

Round the World of Wireless 318 

Transistor Tuner/Converter 320 

Transistor Superhet Faults ... 314 

A Handy Signal Injector ... 327 

Audio Otciliator Design ... 332 

Making Panel Escutcheons ... 335 
Versatile Gramophone 

Amplifier , ... 336 

End Fad Aerials 341 

a Multipliers 344 

Electronic Vibrato 347 

Cabinet Care 348 

On the Short Waves ... ... 357 

Transistor P re-am p. ... 358 

Club News 362 

The Chelmer 4 365 

A Simple Carbon Microphone 370 

Trade News 373 

Letters to the Editor 377 



=: The. Editor tciV be pirated In consider £ 

— arttctet of a practical nature. Such — 
= articles should be written on one side ss 
ss of the paper only, and should contain ss 
=: the name and address of the sender. = 
= Whilst the Editor does not hold himself — 
= responsible for manuscript*. every = 

— effort will be made to 'eturn them if a ss 
= stamped and addressed envelope is = 

— enclosed. Alt correspondence intended ss 
= for the Editor should be addressed: = 
S The Editor, Practical Wireless. = 
£ George Setenes. Ltd.', Tower House. ~ 
ss Southampton Street, London, W.C.2. = 
S£ Otrlnn to the rapid prooress in the zs 
ss design* of wireless apparatus antS to ^ 
SS OVf efforts to keep reader.' in touch 3 
= irith the latest developments, we flfre = 
— ; no uxinanl't that apparatus described- ss 
ss in our colu nns is not the subject of ss 
H letters patent. ss 

— Copyright in all drautngs. photo- £ 

— graphs and articles published in ss 
= Practical Wiseusss i,«r specifically = 
£ reserved throughout the countries zs 
~ signatory to the Berne Convention and ss 
ss the U.S.A. Reproductions or imitations = 

— of any of these are therefore erpresslu ss 

— forbidden, PSACTTCAI Wtheless ^ 
~ Incorporates "Amateur Wireless." — 

^iiiiitiimmiiiiitiiiiiiiiiimiiiiiiiiiiiiiiiiiitiiimiiii?. 



Finishing the job 

AT this time of year many readers, we hope, are enjoying 
a well-earned holiday, or are contemplating one in the 
near future. Others — sad thought — have already 
had their annual break from the daily task. 

The radio enthusiast, returning from holiday to take up the 
threads of his hobby will most likely be eager to get started 
again, like a lion refreshed. This is the time to consider 
whether enough thought and attention is given to the final 
appearance of equipment to be constructed. 

Too many constructors spoil the ship for a ha'porth of 
tar. Too many pieces of equipment are electrically efficient 
but look like something from Steploe's junk yard. Too many 
units are housed in unsuitable casings — or none at all — 
and too many panels are untidy in layout and finish. 

There was once a popular saying that "it doesn't matter 
what it looks like so long as it works". This may have had 
an element of justification in bygone days but it does noi 
ring true in 1964. Except for purely experimental projects. 
the average piece of equipment built by a constructor of 
average ability and experience, should work quite well at first 
switch-on. But there is no excuse, nowadays, to mar a nice 
piece of construction by slipshod appearances. 

If one is not building from a kit, or from a published 
design, a little more thought on external appearance will often 
bring rewarding results. The placing of controls, etc., on a 
front panel do not have to be exactly symmetrical but they 
should have a semblance of tidiness. 

Knobs do not have to match, but it looks better if they 
do. Potentiometer spindles do not have to be the same length, 
but sawing them to a uniform projection looks neater. Con- 
trols do not have to be labelled, but the use of stencils or 
panel transfers will enhance the appearance. Wooden cabinets 
do not have to be painted or polished but they look better if 
they are. Crocodile clips {and worse) can be used for inter- 
connections but proper plugs and sockets look better and are 
more positive — and safer. 

Also, many enthusiasts do not have a separate radio room 
or even if they do, certain pieces of gear are used in rooms 
inhabited by parents or wives. A poorly finished item can 
be an eyesore to the non-enthusiast! These days neat, 
compact, units are easily possible but there is no reason for 
not trying to make them even more compact if circumstances 
dictate — and to make them as presentable as possible. 

In radio clubs and at exhibitions equipment can often be 
seen which, though built by amateurs, has a crisp professional 
flavour. It should be the aim of all serious constructors to 
reach, within practical limits, this kind of standard. But. at 
least, ihe care and attention given to achieve electrical 
efficiency and neat wiring should be allied to a pride in the 
final appearance. 

As for the inside of equipment- — that is quite another 
storv ! 






Our next issue dated September will be published on August 7th 



318 



PRACTICAL WIRELESS 



August I%4 



<\ 




1& 



$0* 



Willi 



NEWS AT HOME 
AND ABROAD 



Festival QSL- Cards 

for Johannesburg* 

Contacts 

TJURING August, September 
and October this year, South 
Africa's capital city will be pre- 
senting The Johannesburg 
Festival ". Johannesburg's hams 
will be participating in the 
Festival and a special QSL-card 
will confirm all contacts with local 
amateur stations during the festive 
period. In addition, an award 
will be given to stations sending 
a certified list of contacts (no 
QSL-cards) made in accordance 
with specified rules, to the 
Awards Manager, P.O. Box 
7227. Johannesburg. Republic of 
South Africa. The rules require 
that Dx stations, outside Zone 38, 
must contact five Johannesburg 
stations during the period of the 
Festival. 'Phone, s.s.b., a,m. or 
mixed contacts with a minimum 
report of RS 33 or RST 338 will 
be acceptable. 

Short wave listeners can also 
qualify by sending a certified list 
of the required number of 
stations heard, as provided by the 
rules, to the same address. 

The award, presented on the 
inside of a folded card, tells the 
story of the growth of Johannes- 
burg in story and colour 
illustrations. 



Radio Show Returns with a Difference 

A FTER an absence of two years, the Television and Radio Show 
"* will be back at London's Earls Court m late August, but with a 
difference. Following on the success of 1963's " trade-only *' shows 
staged by the different manufacturers, this year's, Radio Show will 
tey restrictions on public viewing time, leaving periods when visiting 
radio dealers will be able to " take in " the displays at leisure in a 

relatively deserted Earls Court. 
This step has been taken to com- 
bat criticism f-om the trade that 
much of the benefit of the show 
is lost when dealers have to con- 
tend with a public crowd in order 
to see all the exhibits, as they 
have had to in the past. The first 
two days of this year's show then, 
will be strictly for the trade. The 
public will be admitted on 
August 26th but then only from 
11 a.m. onwards, as on seven of 
the remaining ten days of the 
exhibition the hours of 9,30 a.m. 
to 11 a.m. will be reserved, once 
again, for the trade only. 

What this means, in fact, is that 
the public is left with August 
26th to September 5th (except 
Sunday) when they will be 
admitted from 11 a.m. (10 a.m. 
on Saturdays) to 9 p.m. 



U.S. FIRM TO 

MANUFACTURE 

E.E.V. TUBES 



AS a result of arrangements 
recently made with Com- 
pagnie Generale de Telegraphic 
Sans Fits (C.S.F.) in Paris, 
English Electric Valve Company 
products may now be manufac- 
tured in the U.S.A. 

The two companies have 
exchanged manufacturing infor- 
mation, so that each now makes 
certain products of the other, and 
this facility is now available to 
Warnecke Electron Tubes Inc., in 
Chicago, U.S.A., which is a sub- 
sidiary of C.S.F. 



Royal Albert Hall Gets Audio Boost 

AA/'HEN the BBC recently televised a " beat " music show from the 
Royal Albert Hall, screams from the teenage audience effec- 
tively drowned much of the output from the hall's audio installation. 
To prevent this problem arising on the second occasion that " big 
beat" performers and groups and hundreds of teenagers at the 
Albert Hall combined to provide BBC-2 with its Top Beat show, 
Standard Telephones and Cables Limited, who originally installed 
the Hall's amplification system, brought in extra loudspeakers and 
stepped up the power to boost voices and musical instruments above 
the screams. 

STC engineers increased the regular installation, consisting of 
three 45W amplifiers, to over 300W for the performance. 



August, 1964 



PRACTICAL WIRELESS 



319 



COMMERCIAL RADIO FOR THE ISLE OF MAN 



A COMMERCIAL radio 
station for the Isle of Man 
has been given the sanction of 
the Home Office. 

This was established by a 
recent Press release in which it 
was stated that under an agree- 
ment with the Isle of Man 
Government (in which Pye of 
Cambridge have entered) a com- 
pany will be set up to operate a 
radio broadcasting station on the 
Island. 



Final details of the company 
and the concession granted to it 
remain to be finalised, but the 
principal conditions have been 
settled. Under the agreement, the 
company will provide a service 
on both the medium wave and 
v.h.f. bands and to broadcast 
news and items of interest. 

Pye have been acting as techni- 
cal advisers to the Isle of Man 
Government on the project, 
undertaking detailed radio sur- 



Amateur Radio Exhibition Dates 



'THE Radio Society of Great 
Britain has announced the 
dates for its Exhibition this year, 
as October 28th to 3 1st. 

Once again this year, the venue 
for the exhibition will be the Sey- 
mour Hall, Seymour Place, 
Marble Arch. London. 

The 1964 International Radio 
Communications Exhibition will 
follow the style of previous 
shows, with manufacturers, retail 
firms, amateur organisations and 
technical publishers taking stand 
space in the hall. To accommo- 
date extra exhibits, the balcony 
of Seymour Hall will be open, 
and occupying the stage at one 
end of the Hall will be a special 
presentation, illustrating the part 
played by radio in ships. 



As before, amateur radio 
stations GB3RS and GB2VHF 
will be operating from the exhi- 
bition, making contacts on 
70cm and 2 and 4m bands and 
other wavelengths, throughout 
the duration of the show. 
Amateur TV enthusiasts will be 
providing demonstrations and a 
c.c.TV installation will be in 
operation. The armed services 
will once again be providing 
interesting exhibits as will other 
government bodies. 

Various presentations of 
awards will be made during the 
show, including a £130 com- 
munication receiver to the holder 
of a lucky ticket. The doors will 
open daily from 10 a.m. to 9 p.m. 
The price of admission will be 3s. 



veys of the Island and providing 
technical recommendations con- 
cerning both the transmitters. 
These recommendations were 
passed to the British Post Office. 

The specific frequency recom- 
mended in the medium wave 
band is entirely available for the 
purpose and will cause no inter- 
ference with any existing broad- 
casting service in the United 
Kingdom, It is proposed to con- 
fine the hours of transmission in 
the medium wave band to day- 
light and under these conditions 
the station cannot interfere in any 
way with continental stations. 

The allocation of a medium 
wavelength at the outset is essen- 
tial as only a small minority of 
set owners would be able to tune 
into v.h.f. programmes. 

The station will be broadcasting 
under the authority of the Post- 
master General's Wireless and 
Telegraphy Act, and new legisla- 
tion in the Isle of Man Legisla- 
ture will ensure high standards of 
both public broadcasting and of 
the advertising material. 

A complete broadcasting 
station with medium wave and 
v.h.f. transmitters and a studio 
was shipped from Cambridge to 
the Isle of Man during June. 



LORD FRASER GUEST OF VETERAN HAMS 



I ORD FRASER of Lonsdale 
1 was the principal guest at the 
Annual Reunion Dinner of the 
Radio Amateur Old Timers" 
Association which was held 
recently in London. In 1926 
Lord Fraser, then Captain Ian 
Fraser, was President of the 
Radio Society of Great Britain, 
himself holding a transmitting 
licence. 

At the dinner some eighty 
" hams ", all of whom had had a 
transmitting licence more than 
twenty-five years ago, heard 
Lord Fraser speak of the mile- 
stones in the history of amateur 
radio and of his own experiences 
as a voung wireless enthusiast. 
Recalling how. in 1927, British 
radio amateurs decided to demon- 
strate to a BBC reluctant to begin 
overseas transmissions. that 
music broadcasts to Australia 
could be reliable, Lord Fraser 
said: 



" I well remember how, with 
the help of the transmitter of Mr. 
Gerald Marcuse. a leading ama- 
teur, we organised a transmission 
from Britain to Australia in the 
early hours of the morning, The 
High Commissioner for Austra- 
lia and some leading Australian 
artists then in Britain put on an 
hour's programme from Mar- 
cuse's house in Caterham to 
Australia, and the Australian 
broadcasting stations gave it 
national coverage. 

" So anxious was Marcuse to 
get his signals across that he 
overran his generators and the 
programme only lasted for a few 
minutes before they burnt out. 
Nevertheless we had spurred the 
BBC to action, and very soon 
they produced the Overseas 
Division which began world-wide 
broadcasting." 

Commenting on the experi- 



mental work and services to the 
community performed by radio 
amateurs, Lord Fraser went on to 
say: 

** I suppose that in every 
scientific field the amateur has 
made his contribution. Certainly 
in the wireless field much experi- 
mental work — hardly to be digni- 
fied by the name of fundamental 
research, but nevertheless of con- 
siderable intrinsic value and of 
great educational value — was 
done . . . When the General 
Strike occurred in 1926 I was a 
freshly elected M.P., and I 
remember helping to organise a 
skeleton service which offered to 
enlist hundreds of amateurs all 
over the United Kingdom who 
could communicate with each 
other if official services broke 
down. In fact there was no 
breakdown and we had no work 
to do, which greatly disappointed 
us." 



— ■- 



320 



PRACTICAL WIRELESS 



August 1964 



Transistor 
Tuner/Converter 

I, 2 or 5 Transistors 
Optional i.f. Strip 
Plug-in Coils 

BY F. NEVILLE HART 



■■ ' vs:: ' ■.;: 





be taken to see that the shank and the spindle 
of the tuning gang are concentric, otherwise any 
undue pressure wiJl make the faster of the two 
slow motion movements bind. This assembly 
has approximately 5 degrees either way of 36 to 
1 movement, which makes selection very easy. 
Then the movement changes in eiLher direction, 
to 6 to 1 for quick tuning. 

Two Transistor Tuner 

As with the Denco coils for valve sets, the 
bottom end of each oscillator coil is brought to a 
different pin on each range to connect with the 
correct padder capacitor. Although medium and 
long wave ranges are made, there is no advantage 
in providing for them in this design, and in any 
case, since Range 1 and Range 5 use the same 
padder pins, one would have to choose between 
the two, or incorporate a simple 
switch arrangement on the front 
panel, selecting the appropriate 
padder. 

The coils are supplied in alu- 
minium boxes which are used for 
screening cans, suitably cut and 



This is how the tuner looks when 
complete except for the i.f. strip which 
wilt be described in our next issue. 



niHIS versatile unit can be built in a number 
I of ways, depending upon the pocket and 
J- requirements of the constructor. In the first 
place it can be made as a one transistor tuner 
as described in the March 1963 issue of Practical 
"Wireless, in which we had to wind on an extra 
coil for the base, on to the plug in coils designed 
by Denco for valve circuits. 

This company has now produced a whole range 
of similar plug in coils for transistor use, still 
using B9A Noval valve holders, but with the 
new advantage of the coil former having nine 
pins, which hold the coil very firmly indeed. 

Since some readers asked uf the tuner could be 
made more selective, an r.f. stage is added in this 
version. In addition, the set has been designed 
to take a "plug in" l*6Mc/s i.f- strip with volume 
control. This can either be used with the output 
taken to an audio amplifier through the crystal 
diode, or, as an extension of the first part, as a 
double superhet into the aerial circuit of any 
medium band* radio. 

Choice and construction of a cabinet is left to 
the reader, but one made of three ply, leaving 
room for the battery, and with a section of the 
top hinged to facilitate coil changing, is suggested. 

The dial assembly is easily lilted but care should 



drilled. The lids of the cans have 
to be mounted at the same time 
as, and under, the B9A valve 
holders and care must be taken 
to see that they make contact 
with the metal rim of the holder. 
These should be cut as in Fig. 2. 
First make two straight cuts across the centre, 
£in. apart, the centre removed, and each end of 
the slot cut down to the knurled edge. Then 
with a round file, shape the hole to take snugly 
the ceramic or bakeUte portion of the valve 
holder. One of the metal ends of the latter can 
now be inserted and the other end gently forced 
into place. 

This being done before mounting on the paxolin 
chassis, it can be ensured that some portion makes 
contact so that when the screening can is screwed 
on it is properly earthed. It is easier to insert the 
fixing screws if they are round headed. 

The requirements of the tuning capacitor are 
that it must have ceramic insulation and each 
portion 300pF, with a minimum capacity of llpF. 
The Jackson "F" three gang 300pF fits these 
conditions admirably. 

Solder on three wires to the stators before 
mounting, as these junctions are (inaccessible 
afterwards. Mount the tag strip first, using 
countersunk screws to avoid fouling capacitor 
moving plates when fully open. It is also neces- 
sary for the same reason to "bush" up the 
capacitor with washers or fairly wide nuts on 
the fixing screws or the moving plates will not 
open to the fullest extent. 



August, 1964 



PRACTICAL WIRELESS 



321 



COMPONENTS LIST FOR TUNER SECTION 



R5 2-7kO 

R6 I Ok ii 

R7 I -2k Q 

R8 I -8k 12 



Resistors: 

Rl 27kQ 

R2 IOkQ 

R3 l-2kQ 

R4 Ikn 

All i-watt carbon, ± IO° 

Capacitors: 

CI 0-Q05yiAF disc ceramic C2 00l,uF mica 

C3 05/iF mica 

C4 O'OI^F mica 

CS 2/xF 6V electrolytic 

C6 2000pF mica 

C7 OOI^F mica 

C8 G003^F disc ceramic 

C9 0-OI/iF mica 

CIO 50^F 25V electrolytic 

CI I 250pF mica 

Cpl 340pF Cp2 960pF 

Cp3 2000pF 

Variable Capacitors: 

VCI, VC2, VC3 3-gang, 300pF per section 

(Jackson Bros, Type F) 
TCI-TC7 3-30pF beehive type trimmers 



Tr2 OC17I 



Tl 
T2 
T3 



Transistors: 

Trl OCI7I 
Inductors: 

1FTI Denco Maxi-Q 1 6Hc/s i.f. transformer, 
TypelFTI6 

Denco plug-in transistor coils. Aerial (Blue) 
Denco plug- in transistor coils. R.F. (Yellow) 
Denco plug-in transistor coils. Mixer 
(White) 
(Note: ranges of Tl, T2 and T3 to suit require- 
ments. Range 3= l-67-S-3Mc/s. Range 4= 
50-ISMc/s. Range 5=IO-l5Mc/s 
Other items: 

Jackson Bros. 6/36 drive assembly, complete with 
dial. Number 4103. Four B9A valve holders. 
One blank Denco 9-pin coil former. Slider 
switch or similar smatl on-off switch. 
Paxolin (7 x 4|in.); two angle brackets (3f in. long 
x •fin.) ; two pieces aluminium sheeting (If x 
ty\n.)\ 10-way tag strip 3^in. long with end tags 
and tags 4 and 7 as earthing connections; 30 nuts 
and bolts, 1 1 with countersunk heads; 10 solder- 
ing tags; aerial socket; two miniature crocodile 
clips; sleeving; 6V battery; battery clips. 




TCI to TC3 are 3-3Cp F , see text far modification to colls 
tor appropriate trimmer 



Fig. I : The circuit of the tuner. 
Fig. 2 (pictorial inset): Modifying the coil cans for accommodation on the chassis. 



The oscillator trimmer TC7 can now be soldered 
onto the tuning gang, the "rtalk' 1 onto the body 
with a hot iron, after scraping and tinning the 
spot where it is to go. The L Tivc" end must be 
soldered to the stator tag. When wiring up 
positive earth wires do not forget to connect a 
wire to each of the two contact springs in the 
middle of the gang capacitor, taking care to see 
that there is enough clearance for the moving 
plates. 

Cut and drill the base panel, mount the angle 
brackets, the tag strip and i.f, coil (Denco I FT 16). 
Also mount the valve holders (4). remembering to 
put soldering tags onto each of the fixing screws 



where indicated in the layout. This also applies 
to a screw on each angle bracket. 

The dial assembly can be mounted after all 
the base wiring is finished but drilling holes 
should be marked to coincide with the angle 
brackets. The side pieces, of aluminium fixed 
onto the dial, serve the dual purpose of extending 
the screen and of supporting the dial, and to 
accommodate the sliding switch. If it is intended 
to use the i.f. strip, the left hand one will have 
to be drilled to take the volume control. Mount 
the switch ready to take the main minus wire 
when assembling. 

Now solder in aU the positive leads with bare 



322 



PRACTICAL WIRELESS 



August 1964 



Wifte. 

coU- 




TbS* 
On/oft switch 



Tags marked V are'earthlng* points on 4-ve line end should all be connected 
together using heavy guage tinned copper wire 

Fig. 3i The main wiring, as it appears on trie underside of the paxoiin chassis. 



tinned 24swg wire, but use a heavier gauge wire 
for connections to tuning gang and across the 
four main soldering tags on the tag strip. These 
should be firmly joined at their bases to form 
a " bus- bar ". It is an essential of short wave 
working that particular attention is paid to efficient 
earthing of all tuning components. Also earth 
the i.f. can. 

It wffl usually be found that the metal around 
B9A valve holders is solderable, so solder on 
an earth wire to the three coil holders, slipping it 
under the slots on the screening can holders. 
Nest wire on the tuning gang leads from the 
stators, having pushed these, suitably insulated 
with sleeving, under the tag strip, before attaching 
to the respective tags on the valve holders. 

Proceed to wire on all negative leads except 
that to the switch. Wire on the resistors, then the 
fixed capacitors, taking care, as these are of 
a miniature kind, to make a quick joint It is 
a good plan to treat these like transistors and use 
a heat sink, such as a long nosed pair of pliers 
with an elastic band around the handle. Transistors 
should be left until the very last 

When all the wiring of the chassis is done, 
mount the transistors. Their positions are not 
shown on the layout of the base panel, but they 
lie diagonally towards the rear of the underneath 
side, approximately under the tuning gang, their 
bases, emitters and shields soldered onto the tags 
indicated on the layout. It is as well to place 



sleeving on each wire and the writer uses a colour 
code as follows: Black for collectors, Blue for 
bases, Yellow for emitters and Red for shields. 
White can be used where needed for base bias 
circuits. 

The output leads are of coaxial cable and 
terminate in a blank. Denco coil former to fit into 
the B9A output valve holder. This is put there 
so that if it is decided to add the i.f. strip, it 
has merely to be plugged in. The 250pF series 
capacitor is contained in this former, two holes 
betas drilled near the respective pins, through 
which one wire from the condenser is pushed, 
and the output earth wire through the other hole. 

Separate Aerial and R.F. Trimmers 

One of the disadvantages of these plug in coils 
when they were designed for valve sets was that 
variations of trimmer capacitance of each 
individual range were not possible, for only four 
pins were fitted. But now the makers insert nine 
pins in the formers, and pins 2, 3 and 4 on the 
aerial and mixer coils are left blank. As this article 
covers Only the three short wave ranges of these 
coils, what better than to utilise these blank pins 
for trimmers ? 

A small modification is needed on each aerial 
and mixer coil only, as it is found that the oscilla- 
tor trimmer (TC 7) needs no adjustment on the other 
bands after setting for band 5. Modify the coils 



August, 1964 



PRACTICAL WIRELESS 



323 



as follows: — 
Range 3. Solder a thin insulated wire from 
pin 6 to pin 3. Do this on both 
aerial and mixer coils. 
Range 4. Solder same as above from pin 6 to 

pin 4, both coils. 
Range 5. Again wire up both coils pin 6 to 

pin 2. 
When doing this, first insert the coils into a 
loose 89A valve holder, in order to keep the pins 
from moving when they get hot, as the plastic 
former melts at rather a low temperature. Similar 
connections will be provided on the valve holders 
to the trimmers, i.e.: — 
Range 3. Aerial coil holder Pin 3 to TC3 
mixer „ „ Pin 3 to TC6 

Range 4. Aerial ^ „ „ Pin 4 to TC2 

mixer „ „ Pin 4 to TC5 

Range 5. Aerial „ „ Pin 2 to TCI 

mixer „ „ Pin 2 to TC4 

Alignment 

This is made very much easier with a signal 
generator, but the following hints will assist 
greatly those who do not possess this invaluable 
aid. Note that the Range 5 mixer coil uses 
second harmonic in the interests of stability. 
Alignment of this stage is carried out in the 
normal way, however. First start by placing 
Range 5 coils in the holders, with the tuning dial 
at about 80. 

The output connection from the tuner to the 
existing radio will depend upon the type of set 
used. With a valve radio which does not use a 
ferrite rod aerial, take it to the " live " side of 
the tuning gang, or if this is inaccessible, to the 
aerial terminal, the wave change switch being, 
of course, switched to medium waves. With 
transistor sets, the output should have a miniature 
crocodile clip and be taken to the connection 
from the base of the mixer transistor to the ferrite 
rod aerial. 

The ideal way is' to fit a two-way slider switch 
on the front panel so that the mixer base is 
connected to the centre contact. One side goes 
to the ferrite rod for normal listening, and the 
other to a socket on the side, in which to plug 
the tuner. This socket is also wired up to a 
normal base bias circuit of 56kl2 resistor to battery 
negative and 10kO resistor to battery positive 
of the radio circuit. One could not use the 
existing base bias because it will be by-passed 
internally by a blocking capacitor. 

Unfortunately, many transistor radios have not 
the room to mount this refinement, but it avoids 
the risk of medium wave band interference from 
the ferrite rod aerial. A certain amount of fine 
tuning can be achieved by varying slightly the 
radio's tuning dial. 

Connect the earth wire of the tuner to earth 
terminal of the radio, or the chassis. It is not 
advisable to connect to the chassis of an a.c./d.c. 
radio, or use an earth connection to the tuner 
with any mains radio. Sufficient earthing will be 
made through the mains. 

After having thoroughly checked tuner for any 
circuit errors, switch on both sets. Turn the slugs 
of all the coils until they are about half-way out, 
with the trimmers also half-way. Tune the dial 
of the tuner to about 80. The dial of the radio 
must be to its highest frequency, somewhat higher 



than Radio Luxemburg (208m). This should be 
as near as possible to 1.6Mc/s but more probably 
about 1.4Mc/s. In that case, the i.f. coil slug 
will have to be tuned to this frequency. When 
any loud signal is received on the tuner, it should 
be adjusted until maximum volume is obtained. 

If using a signal generator, refer to the alignment 
chart which follows. If not, a fairly strong signal 
should appear in the 25m band at about 80 to 
90 on the dial. Adjust the coil slugs and the i.f. 
slugs for maximum output. Shift this gradually 
by moving the oscillator slug, followed by the 
mixer and aerial slugs until the top of this band is 
about 89 on the dial. 

The trimmers TCI, TC4 and TC7, should be 
about half-way in, although finally they may have 
to be in further when aligning 13m and 10m 
bands. Next try for the 19m band, which should 
come in with the top of the band at approx, 61 
on the dial. Then look for the 13m band which 
should come in between 30 and 35 on the dial. 
Here, the trimmers will have to be adjusted. It is 
probable that the aerial trimmer will have to be 
furthest in, the mixer and oscillator about three- 
quarter way in. 

Some patience will be needed to bring in the 
10m band, which should fall between 15 and 20 
on the dial. Instability around this end of the 
dial may be due to a poor earthing connection, 
or the 0.003/xF bypass capacitor across the mixer 
resistor will have to be reduced to 0.002 uF. 

It may also be found that below 10 on the dial 
there is some break-through of stations on the 
fundamental frequency of the mixer coil. This is 
not important as there is little of interest here 
anyway! Repeat the whole process until satisfied. 
The 15m amateurs should be strong about 35 on 
the dial, and the 20m at about 67. 

Align Range 4 coils next The slugs should be 
one-third way out. Start at the low frequency end 
with the 49m band between 75 and 80 on the dial, 
41m band 60 to 64. 31m band 37 to 40, 25m band 
24 to 25, and 19m band 7 to 10 on the dial. The 
makers of the coils state that the Range 4 coils 
coverage is 20 to 60 metres, but they seem to take 
in the 19m band quite efficiently with 20m ama- 
teurs at about 12 on the dial. This is an advantage 
for it saves coil changing at times. Do not move 
oscillator trimmer TC7 after setting for the Range 
5 coils. For Range 4 coils, the TC2 will probably 
be half-way and TC5 three-quarter way in respec- 
tively. 

Next align Range 3 coils which take in the 160m 
and 80m amateur bands. The slugs will be: oscilla- 
tor half-way, mixer half-way, and aerial one-third 
way in. Trimmers. TC6 mixer one-quarter way in, 
aerial fully out (TC3). 

The 160m band can often be found by a brcw.d 
tuned bubbling noise, presumably caused by so.ne 
powerful direction beam. This should fall aJvout 
80 to 84 on the dial. As the il, is 1.6Mc/s, the set 
will probably burst into oscillation near tfiis. at 
the I.f. end of the dial, giving one some indication 
in alignment. The 80m amateur band should be 
between 25 and 30 on the dial, the trimmers being 
operative here. 

To those possessing a signal generator, the 

— continued on page 369 



324 



PRACTICAL WIRELESS 



August, 1964 



Transistor Superhet Faults 

SOME HINTS ON LOCATING FAULTS WITHOUT INSTRUMENTS 



FAULTS which may occur in the usual type of 
transistor superhet can generally be located 
quite rapidly if the task is undertaken in the 
correct way. The first step is to determine whether 
the mixer, i.f. amplifier, or audio amplifier is 
responsible. The stage where the fault arises is 
then located. Finally the faulty component or other 
defect is isolated. 

Many faults produce particular and character- 
istic symptoms, and can be located without 
instruments. In the testing methods described some 
tests require instruments, and these are included 
because a meter, set of headphones, or other test 
equipment will often be available, and can be used 
to simplify checking suspected stages. 

The circuits are representative of popular pocket 
and full-size transistor super hets, and most points 
apply to all such receivers, even when circuit 
details vary. Stages are dealt with in their logical 
order, but the first step should be to refer to the 
type of defect described. 

Mixer 

This uses the first transistor, Trl in Fig. 1, and 
includes the ferrite rod aerial with its windings, 
oscillator coil, and variable tuning capacitor, with 
associated trimmers, etc. Typical mixer stage faults 
include reception on one band only, inability to 
tune correct wavebands, poor sensitivity, parasitic 
oscillation, and flat or ineffective tuning. 

In Fig. 1, with the wavechange switch at A, the 
long wave aerial winding L.W., trimmer T3, 
capacitor C2, and trimmer T4 are not in use. So 
if m.w. reception is good, but l.w. reception 
faulty, investigation can be confined to these items, 
and wiring to them, including the switch. Faults to 
check include open-circuited or wrongly connected 
l.w. winding, a short in T3" or T4, or C2 defective, 
or of wrong value. 

If proper m.w. reception is not obtained, T3,~ 
T4, C2 and the long wave winding L.W. can be 
ignored, and even temporarily disconnected, in 
a home built receiver. Check that point 1 on the 
m.w. coil goes to positive line for m.w. reception. 

If m.w. reception is poor, and attempts to align 
aerial and osc. coil fail, a simple test is to dis- 
connect the m.w. winding at 2, and temporarily 
take this to a 300pF or similar variable capacitor 
wired from m.w. winding to positive line. If 
individual adjustment of this new capacitor, and 
the usual tuning capacitor, provides many stations 
at good volume, there is probably no fault except 
wrong alignment. 

To secure alignment, aerial and osc. coils must 
temo simultaneously, with a frequency difference 
equal to the receiver intermediate frequency (often 
470kc/s). This will only be so if all capacitor 
values are correct. When the temporary tuning 
capacitor described gives good res "Its, c>>eck VCl 
for shorts due to long fixing bolts, and see Tl 



by R. F. Graham 



opens fully. T2 may be checked, and fully 
opened, and point 2 reconnected. If ganged tuning 
is still impossible, C4 should be replaced. 

If the temporary tuning described gives no 
results, check m.w. winding for continuity 
(meter, or phones and dry cell). Also check 
the coupling winding, and connections. Osc. 
coil windings can also be checked. Wrongly wired 
pins may prevent results. The circuit can be tested 
from collector (3) to negative line. No circuit indi- 
cates defective windings in IFT1, or osc. coil, or 
wrong wiring to these. 

If the stage still does not operate, Rl, R2, R3 
and CI and C3 should be checked. Resistors or 
capacitors are sometimes defective, and may have 
a loose end wire, or may have been overheated. 
Colour coding should be checked. 

If all the previous points are in order, Trl is 
suspect. When m.w. results are good, checks can 
be confined to l.w. winding, T3 and T4, C2 and 
switch, as mentioned, if l.w. results are poor. 

Incorrect coverage with VCI nearly open is 
generally due to Tl or T2 being screwed down too 
far. Coverage with VCl nearly closed depends on 
the position of the m.w, winding on the rod, and 
on the osc. coil core position, in addition to C4. 

Oscillation with VCl nearly closed probably 
indicates this is reaching the intermediate fre- 
quency, due to the i.f. being too high, or the m.w. 
winding being too far on the rod. 

Oscillation with VCl nearly open may often be 
cured by adding a 100-50011 resistor at 4. 

I.F. Amplifier 

This has two transistors, Tr2 and Tr3, and 
provides amplification at a fixed frequency (often 
470kc/s). When tuning and band coverage are 
correct, but sensitivity is low, the i.f. amplifier 
may be responsible. 

With a local station tuned in, the cores of IFT1, 
IFT2 and IFT3 should all have a definite peak 
giving best results. If so. these transformers are 
probably in order. If any transformer cannot be 
tuned in this way, check wiring to it. If wiring is 
correct, and each winding is continuous, the inter- 
nal capacitors CI 2. CI 3 and C14 may be defective 
or disconnected from lengthy soldering. 

When each i.f.t. can be tuned to a definite point 
giving best results, leave them untouched. A short 
aerial may be temporarily connected to point 2, if 
no signal to work with is heard. 

If oscillation begins when the i.f.t. cores are 
peaked, check that leads to Tr2 and Tr3 are 
short. If so, check values of Rll and R12, and CIO 



August, 1954 



Wtevechanqe 
switch 




7 vc7 Tl 



fig I : Mixer and i.f, stages of a typical receiver 



and CI I. In some receivers, Lf.t.'s have to be very 
slightly staggered (off tune) to maintain stability. 
If oscillation persists, any fairly large capacitor 
can be temporarily connected across by-pass 
capacitors C5, C6, C7, C8 and C15 (Fig. 2) to 
check them. 

If gain is still low with i.f.t.'s peaked, resistors 
R4. R8, VRI, R5, R6 and R7 should be checked. 
If these are in order, Tr2 and Tr3 are suspected. 

Tr2 and all associated items can be checked by 
temporarily taking lead 5 to Tr3 base, point 6. If 
results are then quite good, investigation is con- 
fined to Tr2, IFT2. R5. C6, R6. R7 and C7. Tr3 
and items in that stage can be checked bv 
temporarily taking collector 7 to IFT3 at point 8 
This isolates IFT2. Tr3, etc. 

If necessary. Rlj. R12. CIO and C1I can be 
checked by removing them. The receiver should 
work quite well, and be siable if the i.f.t.'s are 
staggered, If phones wired from point 9 to posi- 
tive line give good results, the whole circuit in 
Fig. i is in order. 

A stage-by-stage check can be made by dis- 
connecting the diode at 10 and temporarily takins 
it to point 5. With a short aerial added at 2, a local 
station should give reasonable phone results. If 
not, the mixer stage is not working. 

With the mixer working, taking the diode to 
point 11 brings in Tr2 and IFT2. If results are 
then good, this stage is working. If results cease, 
investigate the Tr2 stage as described. 

If results are good with the diode connected to 

11. but not when normally connected, check the 

Tr3 stage as described. If results are good with 

.the diode connected to 11, but not when" normally 

connected, check the Tr3 stage as described. 

If loud, clear reception is obtained with phones 
from point 9 to positive line, but the receiver does 
not operate, investigation can be confined to the 
audio amplifier, Fig. 2. 



First A.F. Stage 

Wrong operating voltages here often cause audio 
distortion. Phones across the driver transformer 
primary P should give much amplified signals, 
compared with those heard from the diode. If so, 
the amplifier Tr4 is in order. If amplified signals 
are not heard from Tr4. check connections to it, 
and resistors R13. R14. R15 and capacitor C16. 

A similar additional a.f. stage may be present, 
with a resistor instead of the primary P. If so 
check this with the phones first. 

Output Stage 

This has two transistors, Tr5 and Tr6. Faults 
in this stage cause distortion, heavy battery drain 
or overheating of Tr5 or Tr6. When good signals' 
are heard from Tr4, but speaker results are 
distorted, the values of R17 and R18 are first 
suspected. These are usually important, and should 
be within 5% of the specified values for the par- 
ticular transistors at Tr5 and Tr6. 

If a meter at point 12 shows a heavy current, 
R17 is probably too low in value, or R18 too high 
in value. If so, reduce RI8 slightly, until the 
average type of output stage takes about 2mA to 
4mA or so. with no signal, peaking up to 1 5mA 
to 25mA or so. with good speaker volume. R18 
may be shunted with other resistors, to achieve 
this. On no account switch on with no resistor in 
the R18 position. 

If the meter at point 12 shows almost no current, 
reduce RI7 for increase R181 until current is as 
just described. R19 is often 3-3.0 to 5-6fl or so, and 
bad results sometimes arise from using 33 to 56fl 
in error. 

If good signals are heard at primary P of the 
driver transformer, but no speaker reception is 
obtained, check driver transformer connections and 



326 



PRACTICAL WIRELESS 



August, 1964 



windings. With phones from 13 to 14, or from 13 
to 15, results should sound much the same as with 
them across the primary P. If not, that half secon- 
dary is suspect. 

Collector currents may be checked by placing 
the meter at 16 and 17. No-signal and average 
signal currents should be fairly equal. If not, Tr5 
and Tr6 are not matched, and proper results will 
not be possible until they are replaced. 

If the output transformer is in order and 
correctly wired, there will be continuity from 12 
to 16, and from 12 to 17. 

Speaker 

This should click loudly if momentarily connec- 
ted to a small dry cell. If not, the speech coil or 




Fif 2 ' Dmer and push-pull output stages of a typical receiver 

pigtail leads are suspected. If results are distorted 
or scratchy, the cone can be moved in and out 
about Ain. with careful finger pressure. If the 
speech coil is heard to rub the magnet assembly, it 
requires re-centering. This is usually done by free- 
lag bolts or nuts which hold either the magnet, or 
Hm cone spider. If the cone moves with no audible 
scratching, leave it unchanged. 

Distortion may arise from wrong impedance 
matching. This is generally due to a wrong output 
transformer, or trying to use a speaker with the 
wrong impedance. Most transformers are for 312 
«r similar speakers. A 15fl or other speaker 
a different transformer. 



Noisy Reception 

If the noise is unchanged, with VR1 in any 
position, it arises in the audio amplifier, Fig. 2. 
Loose connections or bad (dry) joints may be 
found by moving leads, etc., with an insulated tool, 
with the set working. 

A continuous hiss may be caused by Tr4, which 
Bay be defective. Or R13 may be too low in value, 
or R14 too high in value, so that Tr4 collector 
current is high. Current, measured with a meter at 
18, should usually be 1mA to 2mA. 

|| (hp noiic increases in volume as VR1 is 



turned towards maximum, it arises in the part of 
the circuit in Fig. 1. Bad joints, etc., can be located 
as before. 

A.F. Instability 

This is by howling not influenced by tuning. CI 5 
and CI 7 should first be suspected. If the set has 
negative feedback, and howls when first tested, 
connections to the output transformer may need 
reversing. 

Instability 

If this remains virtually unchanged, at any posi- 
tion of VR1, except for the normal volume control 
effect of VR1, it is arising in the mixer or i.f. 
amplifier, and may be located as already described. 
If the instability begins 
only with VRt near maxi- 
mum, feedback from output 
circuits to aerial may be res- 
ponsible. The aerial, wires to 
it, and connections in parts of 
the circuit in Fig. 1, should 
be reasonably clear of the 
output transformer, speaker 
leads and parts and connec- 
tions in Fig. 2. 

In miniature receivers, a 
fixed capacitor (OOImF to 
0OAp.¥) may be wired across 
driver primary P, or from 
collectors 16 and 17 to posi- 
tive line, to cure this type of 
feedback. 



Equipment 

To locate any of the faults 

described, in the manner 

explained, 500-4,0OQft phones, 

and a dry cell, may be used. 

A simple d.c. multi-range 

meter, or 0— 10mA or — 25mA meter, will allow 

output siage and other current cheeks to be made. 

Coniinuity tests can be made with a 1±V dry 

battery and lkil resistor in series with the meter, 

which should read l*5mA. Test voltages must not 

be applied to transistors. 

Some tests described can most easily be made 
if phone leads have small clips. To test suspected 
r.f. by-pass capacitors, a O'ljuF or simitar capacitor, 
with clips, is useful. Electrolytic capacitors can be 
shunted with a 25/*F to 100,uF capacitor, with 
clips. 

If a meter to measure resistance values is not 
available, suspected resistors can be checked with 
reasonable accuracy with a dry battery and the 
meter. If the battery voltage is divided by the 
current reading in mA, this gives the resistor value 
in k-Ohms. That is : 



= Resistance (k-Ohms). 

mA 
Aerial, osc. coil and I FT windings will usually 
be only a few ohms, while driver transformer 
windings will often be only 10-20fl or so. The 
output transformer primary is usually only a few 
ohms, and the secondary S is of almost zero d.c. 
resistance ■ 



August, 1964 



PRACTICAL WIRELESS 



327 



tmiiiiiiiiii 




HANDY 

SIGNAL 
INJECTOR 



j» 



R^-lTMOlffD CRUISE 



SEVERAL excellent designs for signal injectors 
have been described in the past but the one 
about to be described will bear favourable 
comparison, mainly as regards cost, ease of 
construction and ready availability of components. 
A printed circuit construction is used which, 
together with switch and U16 battery, can all be 
contained quite easily in a 35mm film casette tin. 
The total cost inclusive of chemicals, printed 
board, paint and components is under £1 and, of 
course, there will be sufficient chemicals and paint 
left to do quite a lot more printed circuits. 



Circuit Description 

The circuit, as will be seen by Fig. 1, is the 
well-known "Multivibrator" or " Astable 
circuit". This circuit in its valve form was 
described as long ago as 1918 and was originally 
conceived as a square-wave generator. Since a 
square-wave is very rich in harmonics the name 
" Multivibrator " was coined. The circuit 
operates as follows: 

When the unit is switched on, both transistors 
conduct a relatively high level of current, approxi- 
mately 6mA. and this causes a sharp drop in 
collector voltage and a positive-going pulse is sent 
to the other transistor which counteracts the effect 
of the base bias -resistor and switches the transistor 
off. This causes a negative-going pulse which 
switches the first transistor on again. 

Slight unbalance in the components or random 
variations in the current will always, on switching 
on. cause the transistors to go into one of the 
unstable states rather than the other; the circuit is, 
therefore, self-starting. The circuit subsequently 
oscillates between the two unstable states and so 
is quite free running. 

The output produced is of square-wave form at 
a fundamental frequency of approximately 2kc/s 



and. as previously mentioned, is rich in harmonics, 
enabling it to provide a continuous note when 
injected into any receiver. It may be used for 
r.r"., i.f. or a.f. equipment and is one of the most 
useful instruments one can have for testing and 
tracing faults in radios and amplifiers and. as a 
high voltage is not produced, the unit cannot harm 
transistorised equipment. 




Fig. I : The two-transistor circuit for this handy instrument. 

Whilst not really necessary, due to the fact that 
the probe and wander lead socket, if assembled 
as per, instructions, are insulated from the can. in 
the interests of safety when testing equipment of 
the a.c./d.c. variety the can could be easily and 
quickly wrapped with insulating tape. 

Construction 

Obtain first two 35mm film casette tins, one 
llford and one Kodak. The Ilford can is used 
with the Kodak screw top. The Ilford can is 
slightly larger and the Kodak screw top is pre- 
ferred as this has a raised centre, whereas the 



328 



PRACTICAL WIRELESS 



August, 1964 




done either by tracing the outline with tracing 
paper and then transferring this on to the copper, 
using carbon paper and a hard, fine-pointed penal 
or alternatively copying Fig. 3 directly on 10 the 
copper, using carbon paper. 



Fig. 2: Details of the probe used with the injector. 

Ilford is flat. These can be obtained from any 
photographer's and if you have to buy them they 
will cost no more than 6d, for the two. 

Construction can commence with drilling 
casette tin. Centre bottom of can should be 
drilled f\in„ a iVin. hole should also be drilled 
in side of can liin. from bottom, and the centre 
of the screw cap should be drilled I'm. 

A 2in. length of 4BA screwed brass rod should 
next be obtained. Place this in a drill chuck, 
leaving approximately Hin. projecting. Leave i'm. 
of original thread (next to chuck) and shape the 
remaining length as shown (Fig. 2); this can be 
done quite easily in a power drill with a file or 
an ordinary breast drill secured in a vice. 

When this operation is complete remove from 
chuck and saw off the iin, that has been in the 
chuck as these threads will be distorted due to the 





ft 



TC^ 



-ve lead (black)-* Output to probe 

Fig. 4: The complete component layout and wiring diagram 

pressure of the chuck. This completes the probe. 
The next job is to make the printed circuit; the 
materials needed are : 



One piece of -rV' n - thick copper clad board If x£in. 
Ferric Chloride^ these are available from any 
j> industrial chemist at approx. 
Acetate J 1/9 per pint 

"Britfix" Nitrate Cellulose Dope (any Hobbies 

Shop, I '6 tin) 
Fine tipped paint brush 



The Printed Circuit 

The procedure is as follows: First rub the 
copper over lightly with steel wool, then the 
outline shown on Fig. 3 must be transferred on to 
the copper side of the board. This can best be 



Fig. 3: An actual'size representation of the printed circuit 
board (/fin. x |rn.). 

Next the areas thus shown shaded must be 
painted with the dope to resist the etch (the reason 
I use nitrate dope is that it is cheap. A Is. 6d, 
tin will do literally hundreds of circuits, it is very 
quick drying — approximately 20 minutes — and is 
very easily removed by the acetate). 

When painting these areas, if you have used 
carbon paper you may find that two adjacent areas 
will run into each other. Don't worry about this 
but wait until the dope has dried, then you can go 
over the board with a fine-pointed scriber or 
penknife and separate the conductors. 

When this is completed satis- 
factorily, place the board in a 
small dish (I use a 2±in. x 3|in. 
plastic print developing dish) 
and cover with ferric chloride. 
which will remove the unpainted 
areas of copper and leave the 
painted conductors. 

The process takes 45 minutes 
to an hour but can be speeded 
up considerably by placing the 
dish containing board and 
chemical into a larger dish 
containing hot water. The board 
should be agitated during the 
process, using plastic print 
forceps (this is to displace 
removed copper as it tends to 
cling to the board). 

When all traces of uncovered 
copper have been removed 
wash the board thoroughly under running cold 
water and dry with an old cloth. After 
examining the board again to see that there 
are no traces of uncovered copper left take an old 
piece of rag, moisten with the acetate and rub over 
the dope, which will be completely removed _ in 
three or four seconds. After rinsing and drying 
again the board is ready for drilling. 

Take care with the ferric chloride not to get it 
on hands or clothes; it is a poison. When it has 
been used empty it away on a vacant piece of 
your garden and not down the sink. 

All holes should be drilled with No. 60 drill. 
This can best be done from the copper side after 
first lightly centre-punching positions for lead -out 
wires of components, which should be cut to 
approximately £in,, scraped bright with a pen- 
knife, then bent at right-angles to body and 



green 
lead 



August, 1964 



PRACTICAL WIRELESS 



329 



BRAND NEW AM FM (V.H.F.) RADIO GRAM 
CHASSIS AT £13.13.0 (Carriage Paid) 




Chassis size 15 x flj x fiiin, high. Kew manufacture. Dla, 141 x 4tn In 
■1 jalmirs, predominantly gnli] . 2(jl|. 2,1(1 v. A.C only 

n#T#^i£ ea £l r r' Ae \', K " auJ l)i ' juli SOL-keU. Five push buttons— 
""•**■■ f-« ;■?■»* . and tiram. Aligned and tested. O.P. Translormer. 
Tone Control. 1806-1908 >!.; SNHHS80 U.\ *g.sfl Halm. Vaivm SlZT 

S5£ 25 SSS5& "^S ECC83: BP^« 8 x^ud^ufnet 

to nt chassis (table model), 47/S <pnst 5/. ) 

T^^°^ LLtP ^ C i-n I A P***** as/- to purchasers of this ch.nl. 
TERMS: (Chassis) f3.10.0 down and 5 raonthlv Mymants of CS 4 0. Cheat) 
&52J&& for V HF " lji ' 6 - Fe « l * r M. per T »rd "<>u t d bran 2m 

to ,hn™ 1'. I •"««",-» Mc '' 9 " ° T4lu E2^»- Utherwlje similar 

JL^rVL ohaMls - Fnce £ls 1;>.0 WW. mid). TERMS: £3.10.0 down and 
o monthly payments or £2.4.0. 




(normally screwed to chassis) may be 



PUSH-PULL O.P. 
AMPLIFIER £5.5.0 

(fli- Can-. I 

Brand new 200-240 A.C. mains. 
Baas, treble and vol. controls, 
with valves EZS0, ECCS3 and 
2-EL84 giving toll 8 w, Charel. 
12 x 3t x 3|in. With o.p. tran, 
for 3-3 ohm speaker. Front panel 
emoved and used as 'riymg panel" 



LAFAYETTE 

POLLY GUARANTEED 

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Sin, Double plav. 1,200 ft. . , 15/- 

3|in. Long play. 1.200 II.. . 18/- 

5{Ln. Doable plav 1.300 it. 22/6 

Tin. stand play 1.200 ft. .. 12/8 

Tin. Long ptay. 1,800 ft. , . 19/8 

Tin. Double play 2.4ou ft.., 25/- 
THIPLE PLAY 

Sin. 430 ft. , , , . mmmm is/a 

4in. &00 ft, , , . , 32/0 

Sin. l.SOOft. ,., 42/8 

5 Jin. 2,400ft. 55/_ 

Tin. 3,600ft 75/- 

1*. & P. 1/- extra per reel 



BRAND TAPE 

AT RECORD LOW PRICES 

F.V.C, BASE 

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Bin.— 150ft. 8/B 

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Sin.— 300ft 7/6 

4 ret Land over Post Free. 



SELF-POWERED VHP TUNER 

CHASSIS. Covering S«-95 Men. Mullard 
permeability tuner. Dims. 10| x 41 x 
Sin. high. Valve* ECCSo and S — EFSO's 
plus 2 diodes with EZ80 rectifier. Mains 
traniiiiriner. Fully wired and tested. 
ONLY £8.17,8 (carr. paid). Moom diuole 
12/8. Feeder 6d. per yard. 





6-TRANSISTQR 
PORTABLE — Fully Built 

The "SCALA" for only €7.10,6 carr. 
Paid. !,' s j j fljlc high, (.holes of 
colours. Kexine, il.W, ami L.W. 
Fornte aerial. Badery 2/9 eslru. Primed 
circuit. SWly styled. A professional 
lob. 3} In. speaker. Fully tunable M.W. 
and L.W. Superhet circuit. 



iH? ff,' + ^ 200 ^ F * ELECTROLYTIC New STB v. (360 v. surge). 
*n. x l|in. dia.. 5/- each. (Post II-}. *' 



s^ted^testId 1 b\To R e^e S F pat L c H BDILT ""^ othkr wise 

Terms available on Items over £5. Send ed. (stamps will do) for 20 Dane 

illustrated catalogue, Delivery by return. C.O.D. 2/- extra. 

ALL ITEMS GUARANTEED 12 MONTHS. VALVES 3 MONTHS 

G L ADSTONE HAdTo 

"SCALA", CAMP RD., FARNBOROUGH, Hants. 

Farnboioogh 3371 CLOSED SATS. 



"REALISTIC" 

'SEVEN' 




7 Transistor Snuerhet. :«U 

M 1 1 1 1 h at t nut put . 4-1 och speake r , 

Ad turn pun en is mounted on a 

single printed circuit board 

size flj x Gjin. iu one complete 

assembly, Plantlc cabinet, with 

carrying handle, size 7 x 10 x f^^^-~^^^^~^^^~-^i.'^'I 

KJlrj. External Socket lor car fcr~~^^^^-S^^~~^r*" _ ; ^ f 

aerral, Ferrlte rod aerial. £2~ : ^^ : - : ~ :: ~~"-~^^rr '"'1 

Price for the complete parcel '?-~,~Z;r '-""-"; ~'~~~ : ^^~pZZZ~~< : f 

including Traaelstors, Cabinet, ;' -^' f --'_!r'~~'~ : -^rr~~S^™r '. J- 

Sbeaker. etc. and inlr Con- i ■ '■--■•*2» ■ '■' ~-~^~AJ ■ 

atructlou Data: (e -IOC — ■■■■ -. ■ f 

f, i r, « *>9m 1 9.0 : '-^'-.^;"- ■ .-:■■■:■:■■ : y 

PFa Battery 3/B. Data and instructions separately 2/6, Eefunded if von 
purchaBe the porceL ™T?T " '•"* 

Any parts supplied separately. 




4 TRANSISTOR 

MINIATURE PUSH-PULL 

AUDIO AMPLIFIER 

HIGH IMPEDANCE 

PRINTED CIRCUIT. 4in. * n;, n . ^ oyer tran3iormera fe 

J-obri! 5 pvakr.r. ^mtable for microphone, record piaver. guitar and 
P,^ ', V" ^'^O- required. Frequency range 100 ftps, to 25 Kcpg. 
Push-pin output cto« B. Inat ruction sheet provided. Fuliv wSid 
ready for w. Two type,. 2O0 mw. gB/fl; 1 watt, 41/-. P. &*p 2,6 

THIS SUPERB SET for £9 
(Carr. pcf.) 

•-timiiitotor radio covered in sponge-clean 
Doraeour fabric. In latest two-tone shades. 
M.W. and L.W, ferrtte rod, provision for 
car aenal, 2-coioux scale. With FP9 bat- 
tery giving 300 hours use, Welgha under 
4 lbs. With carrying handle. 12 x Tin. hiiib W 
x 4(in. at baK tapering to 21 n. at top. 
Brand new. fully guaranteed. 3 push 
button*. Superhet circuit, oin. L.S. 




5 WATT AMPLIFIER 



?Eu P 11f h ™;!, S'T.iP * 1 ^''". » ,ew b "t.dred only; valves EP9I and 
X.LH4 with metal rcctiher: 6 x 4 x Hln hiirli isin „„ P t?tbs\ -- 
trana. and o.p. with vo, and tone cMii^k: on-otif 'gi-al mpn^ 



GRAMOPHONE AMPLIFIERS AND PLAYERS 

&J5? t , , f^ W l 1t i 1 6i 2; * 4iD ' »"e*k«- Baffle ISi x TJm. 200-240 y. A.C 
£ V*?. *W fw "'-. aad VOi ™ e ' ° Q ' on "*««*■ T« knobs. Eetly 

f,rtr"|' , I P *'-y,'" Ve - VY8S - F 1 ^ ' nd DL8 «- «»-M0 ». A.C. Covered 
JST ™! J ' j It '.V- 'P" fc < r »' > f™>" controls: bass, treble, on-off'vol, 
«/-. poet a--. Double wound enalns Iransfarmer uu-uujvoi.. 

t-ablnet to Bt either type witb plain motor board £S carr. nd Comnlete 
£l0°l1 a Pla w, , ; h 1 ?- J be f J Ut ! 1 ,Ul) - T " t5r!ed cab)I1 "' "* built W 1 KIT) 

Single PUyer in Cab,, m i 13 x 5) In. B.S.R. Monarch 4-speed deck, £8.17.8 . 

HIGH QUALITY PUSH-PULL OUTPUT 
AMPLIFIER 

~i„ v?«? 2w 7, '"-, hi s!!,.<> ver l ™n*- Csed, guaranteed and In excellent 
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f,^fn ^ , ,° *• ° p T ™ n * ** * 9 ^^ ls ohtD s. Choke smoothing. 

F. 4 P. Hi-. V\e can modify for Guitar input for 16/- ex tra, «"»•" 

TAPE RECORDER AMPLIFIER 

FHO"" 1 !* l2S5J^S!l l ' lk , ' * la - Chaaai9 8ize 10 i s 5 * <!"• Valves EF86. 
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back or monitor. (4) Tone. 2 lack socket, lor Tuner,P. U and MlC^iwitoi 
!w * u . t> S''""l" MC : 1 8e | , "™ te w™ !>»*■* containing transformer and rectifler. 
her t-ollaro studio deck only. Price £8,14,0 1ST- P. i P.), 

4-SPEED AUTOCHANGERS 

BSR-UA14 , 

tUKKARD AUTOSL1M 



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Can. 6/- each 



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BATTERY ELIMINATOR 

ma*,}?* C ,° n ™ S?" X" lTSS m mnge > y0v - 1S "^ and 1.4v. 12SmA, 
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Mid e 3 P x^*' l7l °* parate unl " ta re P lac e existing batteries, 4 x 2i x 2,10. 

13 x 8 in. LOUDSPEAKER 

Three ohm. Ceramic magnet of latest type. BRAND NEW. 
49 /6 (post 3/8), 



HEATER TRANSFORMER 

Mains Input giving 6.3 v. S *inp. Size 2| x 20 x lin, (2|in. over winding) 



330 



philips 
paperbacks 



PRACTICAL WIRELESS August, 1964 

an important new technical series 

Presents up-to-the-minute studies of radio, television and 
audio subjects, written specially for the amateur who 
demands complete but not excessively mathematical treat- 
ment. The technical authority behind the books is that of 
the world-famous electrical company Philips of Eindhoven, 
Holland. Eighteen titles are already planned— the first 
seven, published in May 1964, are described below. 



The Tape Recorder c, o. mm 

13s 6d net by post 14s 3d 142pp. illustrated 

Audio Quality c,sio t 

13s 6d net by post 14s 3d m 156pp. illustrated 

AerialS D. ]. W, Sjobbema 

10s 6d net by post I Is 4d 1 10 pp. illustrated 

obtainable from hading booksellers 
ILIFFE Books Ltd. 



the radio servicing series 

A series of books included in the Philips 
Paperbacks, which are grouped together to 
form a comprehensive manual on the repair ot 
radio receivers. 

A. F. Amplification 

10s 6d net by post I Is 3d 109pp. 82 illus. 

Alternating Current* Acoustics 

10s 6d net by post Ms 3d 116pp. 86 illus 

Direct Current & Magnetism 

10s 6d net by post lis 3d 119pp. 92 illus 

Radio Valves 



Dorset House Stamford Street London S.E.I 10s M net by post lis 6d 126pp. 



90 illus 



THE NEXT STAGE 

20 watt stereo I 

If you have already built a mono Audiokit assembly, then it is 
going to be easy and economical to convert it to stereo. If 
you are about to start building Audiokits, you can choose 
stereo straightaway. All the necessary Martin Units are now 
available for converting our famous Formula 1456 to a 20 watt 
hi-fi stereo system, Martin All-transistor Audiokits are the 
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Formula 1456 for 3 o: Formula 1478 for IS a 

SO EASY TO BUILD AND SAVE WITH 




FULLY 
TRANSISTORISED 



STEREO UNITS FOR 
ADDING TO MONO 



MO.NO 
UNIT 1 S-fitane input 



7 6 



rriR RTin 



■elector , . . . IS 
UNIT 2 Fr.!-amp with 

vol. control . . SI 17 6 

UNIT a S-Channcl 

mixer . . £S 18 8 

Matching siiapt-or ea. B 8 

UNIT 4 yre-amp and 

tool control* ,,fl M 
UNIT 5 10 watt power 

iunplltler for II II . . IS 19 8 
UNIT 8 power supply 

(or Unit 5 *2 IB B 

UNIT 7 IB ohm 10 watt power 

AmplUler . . . . £8 12 8 

UNIT 8 Power supply 

for Unit 7 ..HIS 



M 12 6 

£3 IS 



Series "S" Units for all 
stereo construction are 
twice the price of the 
original mono series. 

Kits complete with knobs, 
instruction!, etc. Escut- 
cheons available to re* 
quirement at 6/6 each. 



TBADS ENQUIRIES INVITED 



MARTIN ELECTRONICS, 15-ijS HIGH STREET. 
BRENTFORD. MIDDLESEX 
Details Oi HARTLK ALlilOKITS 
please 

NAME , 



MARTIN ELECTRONICS LTD. ES" 



BLOCK LETTERS 



August 1964 



PRACTICAL WIRELESS 



331 



inserted in correct position on board. 

The protruding ends should then be cut to leave 
about iVin., which should be bent over to be flush 
with [he copper and soldered quickly, using a hot 
iron and cored solder (preferably 22s. w.g.) and 
observing the usual precautions with these 
miniature components and transistors ("i.e. heat 
shunt). The black line down the side of the 
OC44M indicates collector. 

The components when in position and soldered 
should be as shown in Fig. 4. At the points 
marked solder 3in. lengths of thin flexible insu- 
lated wire, inserting these through from component 
side of board. 



Testing 

At this stage the injector can be tested. After 
first ensuring that no short circuits exist on copper 
side of board a HV battery can be connected, 
observing correct polarity. If the green lead is 
now placed on the slider of the volume control 
of a transistor radio the injected signal should be 
beard very loud; if not, check the circuit again, 
paying particular attention to soldered joints and 
ensuring that no adjacent soldered joints are 
shorting. 

If all is well solder a 4BA solder tag to the 
end of the green lead. Next run a 4BA brass 
nut on to the probe about Jin, from threaded end. 
Cut a piece of insulated sleeving about iin in 
length and which fits fairly tightly round the 
threaded rod, push this on from the threaded end 
and right up to the nut. Next push an insulated 
washer over this sleeving and right up 
to the nut, then insert probe, screwed 
end into can, drop another insulated washer over 
rod from inside, followed by another 4BA nut 
and tighten quite tightly, this will effectively 
insulate the probe from the can (it should be 
checked with meter to see if this is so). 

The miniature socket can now be fitted, 
screwing the nut on tightly from inside the can 
and bending the socket tag up slightly. There 
should now be about fin. of screwed rod left 
above nut inside can. 

Solder a 3in. length of thin black flex to the 
negative end of U16 battery and cover the end 
with insulating tape. Take a 2-lin. length of red 
flex and solder to + end of U16 battery Cover 
this with tape. 

The entire printed circuit board can now be 
wrapped completely with insulating material. In 
my case this was a piece of plastic, such as is used 
for toothbrush contamers. secured and wrapped 
tightly round with Sellotape. If this is not avail- 
able the whole board can be wrapped completely 
in insulating tape. 

Now drop the solder tag connected to green lead 
oyer screwed rod inside can and secure tightly 
with a 4B.A. nut (with leads left at approximately 
3in. lengths — this can be done with the component 
board out of the can). Now the red lead from 
board and red lead from battery + can be 
soldered to socket tag inside can. the board and 
battery can now be inserted into can, pushing 
board one side and battery down opposite side. 
Whilst there is not a lot to spare there is quite 



sufficient room to do this; tuck all the wires in 
neatly. 

All that remains now is to remove the screwed 
collar off the switch and fix in the two black leads, 
one from the board and one from battery negative, 
place switch midway between top of board and 
battery, drop can lid over switch, allowing push- 
button and screwed neck to come through a fin. 
hole, whilst holding push-button screw can lid 
on to tin. drop screwed collar over push-button 
and again whilst holding switch stationary by 
grasping push-button screw collar home, thus 
securing switch to lid. Connect a wander clip 
with lead to the miniature plug and the injector 
is complete. 



COMPONENTS LIST 

Rl 22kQ "I 

R2 I50kfi [Miniature^ watt high stab 

R3 270k a f (Henry's Radio) 

R4 22k J 

CI I.OOOpF min tubular (Suflex) 

C2 0-OI/iF\min tubular paper. 150 volt 

C3 0-01/xFj working 

TRI— TR2 OC44M 

S.P. Press on, press off (Wool worths, 9d) 

Radiospares min. plug and socket 

Eveready UI6 J|V battery 



Using Injector 

In practice the injector is used as follows. The 
wander lead is clipped to -J- battery line of tran- 
sistorised equipment or chassis (negative line of 
valve equipment), then in the case of, say, a radio, 
the probe tip is applied to the volume control 
slider with this control turned to full volume and, 
of course, with the set switched on. 

If a note is heard then the fault lies in the r.f. 
or detector stages (from aerial tuning circuit up to 
volume control). If no note is heard the fault lies 
between loudspeaker and volume control. 

Assuming the latter fault to exist the probe tip 
should be applied to output transformer secondary 
and primary windings, bases of output transistors, 
secondary and primary windings of driver trans- 
former, base of driver transistor and so on, 
working back from loudspeaker to potentiometer. 
This injection should proceed until a point is 
reached where the signal is not heard when the 
probe is applied: the fault then obviously lies 
between this point and the one previously checked 
when a signal was heard. 

Similarly if a note is heard when probe is 
applied to slider of potentiometer, the fault lies 
between this component and aerial and the same 
procedure should again be applied, working back 
from behind diode to collector, then bases of i.f, 
transistors and mixer oscillator transistor till a 
point is reached where there is a signal going in 
but none coming out. The fault can therefore 
be localised to a few components which can be 
checked quickly with a meter which should then 
reveal the malfunctioning component. 

As has been pointed out before in previous 

articles on this method of fault finding, the 

injector would probably be of no use if the fault 

is a transistor which for some reason has lost its 

— continued on page 335 



332 



PRACTICAL WIRELESS 



August, 1964 



audio oscillator 



DESIGN 

iiiiimiihiimiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiL 



Transistor oscillator 
circuits described 
and explained. 

By D. K. Greig 



Ladder Networks 

The basis of the stable oscillator is the generator 
network; the ladder network, being basically 
simple, is in common use. Ladder networks may be 
built up by cascading a number of similar r.c. 
phase-shifting sections, using any one of the 
sections shown in Fig. I as a basic element. 

The ladder sections (a) and (b) give a phase- 
shift between the input and output currents, so 
that the input of the transistor, which is connected 
across the pair of terminals on the right-hand side, 
is fed with a current, I out. The input impedance 
of the transistor should preferably be much less 
than the impedance of the network— which is R in 
(a) or the reactance of C in (b)— in order that the 
transistor impedance will not disturb the operation 
of the circuit. This requirement is fairly easy to 
meet. However, a current gain, at low frequency, 
of at least 60 is needed for satisfactory operation, 
and since the input impedance of the transistor in 
grounded-emitter connection may be as high as 
2*5kfi or more at emitter current (T„)=lmA, the 
resulting circuits are of high impedance, and a 
collector supply voltage of 12V or more is needed. 



THE shortage of design circuits for transistors 
is at last now being overcome. The designers, 
however, cater mainly for the experienced con- 
structor. Many designs for audio-oscillators have 
appeared in these pages, but none have been worth 
converting to a generator. 

A recent development in another magazine 
introduced a multi- transistor audio generator 
incorporating a frequency meter. Although the 
design was admirable, the expense made it virtu- 
ally impossible for the amateur constructor. With 
this thought in mind the following circuits were 
used. 

The final professional design can be built tor 
about 50/- and is compact and accurate. The 
introductory sections leading to the description of 
this Wien-bridge oscillator are included for the 
benefit of the home experimenter, who would like 
to try his own hand. The theory has been kept to 
a minimum and much of the mathematics omitted 
so that beginners and experienced constructors 
alike can follow it. 

In the final design it must be emphasised that 
the OC140 is an n-p-n transistor and is therefore 
shown connected the right way round. 

WIEN BRIDGE OSCILLATORS AND 
LADDER NETWORK OSCILLATORS 

The design of resistance-capacitance oscillators 
is similar for transistors and thermionic valves, but 
three factors must be borne in mind. The r.c. phase- 
shifting network is required to feed into the input 
of the transistor, which is of low impedance. 

The internal phase-shift of the transistor will be 
added to, or subtracted from, that of the network. 
When ladder networks are used, the current ampli- 
fication factor of the transistor must be 
appreciably greater than the attenuation of the 
network. 



o * ■» ' WAAAr * o o > ■ 
r v 7 vr iout I in 



I 



* 



*T<> 



lout 



(b) 



AY 



Kj o— 'VvWVVV- 
R 



Vin 



Vout Vin 



I 
I 



Vout 



(c) 



Fig. 1 I Four variations on the bask element of ladder 
networks. 

Sections (c) and (d) in Fig. 1 are voltage-transfer 
networks, and are normally employed with 
thermionic valves. For transistors, the input impe- 
dance, which is connected across the right-hand 
side, needs to be large compared with the impe- 
dance of the network. 

The voltage Vm across the left-hand 
terminals of (d) could be generated by allowing 
the output-current generator of the transistor to 
work into R. No such simple method can be found 
for (c) and this circuit may be dismissed as 
unsuitable. . . 

This way of generating Via sets a lower limit to 
the value of R which may be employed while 
obtaining sufficient voltage for oscillation. The 
condition is R> A re where A is the attenuation 
factor of the network, and is equal to 29 for a 
network of three equal sections. At I 8 =lmA, re is 
equal to 25/U=25Q and R needs to be greater 
than 29 X 25 = 72511 (say l-2kfl). 

To have an input impedance which is sufficiently 
high for satisfactory operation, the transistor needs 



August-, 1964 



PRACTICAL WIRELESS 



333 



to have an a\ (current amplification factor; at 
low frequency) greater than 100. 

These networks therefore are better suited to 
therm ionic valves than to transistors; although if 
transistors of sufficiently high a 1 are available, the 
circuit can be made to work from lower supply 
voltages than when using sections (a) or (b). 

Number of Sections 

The most suitable RC phase-shift networks may 
be built up, therefore, from sections of the (a) or 
(b) type. 

Neglecting the internal phase-shift of the tran- 
sistor for the moment, at least three sections are 
necessary, and the networks could be of the form 
of (a) or (b) in Fig. 2. 

C SS c-js cl"5 iout ( a } 

c T T T i 




Fig. 2. Suitable ladder networks for transistors. 

If the circuit (b) is used, the first R can be the 
load resistance of the transistor, and the circuit 
design is considerably simplified. 

The current attenuation of these networks, at 
the frequency where the phase-shift between the 
input and output currents is 180°, is 29. To allow 
for losses in the input and output impedances of 
the transistors, the a'o should be greater than 
about 60. 

The OC75 is therefore suitable, though transis- 
tors at the tpp end of the OC7I production spread 
should also work in this type of circuit. 

The current attenuation of 29 applies to a net- 
work having three equal resistances and three equal 
capacitances. These are the simplest to design and 
the most commonly used. Also, since the 
grounded-emitter transistor has an input impe- 
dance which is only an order or so different from 
its output impedance, tapered networks are of 
In Me use. 

Operating Frequency 

Single-transistor phase-shift oscillators are best 
restricted to low-frequency operation, where the 
internal phase shift of the transistor need not be 
considered at higher frequencies, both the phase- 
shift and the reduction in a' cause design 
difficulties. 

For instance, with the network shown at (b) in 
Fig, 2, the phase shifts in the network and in the 
transistor vary in opposite senses, so that at high 
frequencies more phase-shift has to be provided 
by the network. The phase shift in each section 
has to be increased, or a fourth section added. 
There is consequently more attenuation. 

With network (a), the transistor and network 



phase-shifts vary in the same sense, and a two- 
section oscillator can be constructed though the 
operating frequency will be somewhat dependent 
upon the particular transistor. Also since any 
shunt resistance across the input capacity of this 
network reduces the phase shift, a higher collector- 
load resistance, and possibly a higher transistor 
output impedance will be demanded. 

The phase-shift in V and hence in the output- 
current generator will be Fa, where Pa is the 
grounded emitter cut-off frequency, and f l 3 = fi/a 1 
where fi = fa/1-22 for alloy-junction transistors, 

800c s Oscillator 

From the fact that single transistor phase-shift 
oscillators are best restricted to low frequency 
operation, the following circuit was designed, 
using the (b) network and a transistor type OC75, 
and shown in Fig. 3. 




Fig. 3: The circuit of an 800c s oscillator using a 3-section 
ladder network. 



The circuit operates at a frequency given bv 
1 

f = ■■ ■ — which for the circuit shown gives 

2-CR v / 6 

650c/s. The transistor input and output impe- 
dances, however, modify this to 800c/s. 

The value of the phase-shift resistors f 1 k 
chosen to be a mean between that which will be 
appreciably affected by the transistor output 
impedance, which is high, and that which will be 
appreciably affected by the transistor input impe- 
dance, which is low. 

With these networks, it is not easy to control 
the amplitude of oscillation without somewhat 
affecting the frequency of operation, and the 
amplitude control may change the frequency by 
approximately 10% or so. 

The gain is controlled by changing the distribu- 
tion of the feedback current between the base- 
bias resistors and the transistor input, the unby- 
passed resistance in the emitter increasing the 
transistor input impedance. The control should be 
adjusted so that oscillation amplitude is smaller 
than that giving objectionable oscillation. 

The Wien-Network oscillator circuit follows on 
naturally from the ladder network system. The 
advantage of the Wien-Network is that the 
attenuation factor is only 3 at the frequency 



334 



PRACTICAL WIRELESS 



August 1964 




Fig. 4i A two-transistor Wien-network oscillator. 

which gives zero phase shift although, since the 
output is in phase with the input, at least two 
amplifier stages are necessary. 



Supply voltage may range from — 3V to — 6V» 
the lower voltage being necessary to obtain 
sufficient oscillation, with VR1 suitably adjusted. 
The output mav be taken from the emitter or 
collector of Tr2 i.e. (R7 or R8). 

This, circuit operates at very nearly the theoreti- 

1 

eal frequency of f = ■ 

Z^VtCaCiRiRs) 

since in fact Cs=Ci and R 7 = R3. With 



1 



2ffC 3 R7 



the capacitances shown the circuit oscillates at a 
frequency of about 3-4kc/s. 

For operation at other frequencies the capaci- 
tances should all be increased or decreased by the 
appropriate figure. (The resistors cannot be 
changed without altering the d.c. conditions). The 
values of C3 and C» should be chosen according 
to the frequency accuracy required, but for Ci and 
C2 the nearest standard values may be taken. 

This circuit is sufficiently uncritical of gain to 
accept the OC70 or the OC71, but if operation is 
required at higher frequencies, it would be better 
to use two OC45's. 



Two Transistor Circuit 

A simple two-stage oscillator of this type is 
given in Fig. 4, in which the Wien-Network is 
R7. C3, C4 and R3. 

Both stages are d.c. stabilised and the lower 
base-bias resistance of Trl also being part of the 
bridge network (R3). The 3-3kfl emitter resistor 







The final, improved design for a Wien-bridge oscillator. 



(R8) of Tr2 is left unbypassed so that this stage 
has considerable a.c. negative feedback. 

VR1 in the emitter of Trl provides a convenient 
means of adjusting the waveform for amplitude 
and distortion, and for temperature compensation 
from one day to the next. The wave-form is good, 
and the short-term temperature stability is fairly 
good. 



Three Transistor Circuit 

A more professional Wien-Bridge oscillator is 
shown in Fig. 5, although the design has been 
kept as simple as possible. This circuit incor- 
porates a thermistor R5 as an amplitude-control 
device, and the output is essentially independent 
of small changes in supply voltage or ambient 
temperature. (A suitable compo- 
nent for R5 is the S.T.C. ther- 
mistor type R53). 

Apart from the frequency 
determining capacitors, only one 
capacitor is required. Conse- 
quently the unit can be built 
compactly, and no difficulties 
arise from phase shift in the 
coupling capacitance. 

The output voltage is IV r.m.s., 
and the circuit operates with 
supply voltages between 7V and 
12V and consumes approximately 
10mA. In Fig. 5, a lower limit of 
9V has been set to the supply 
voltage to ensure low distortion. 
The frequency coverage is 
from 15c/s to 20kc/s in 3 ranges 
(15— 200c/ s, 150— 2,000c /s, 1-5— 
20kc/s) the lower frequencies 
being associated with the larger 
capacitors. The ganged variable 
resistors VR2 and VR3 allow the 
frequency to be adjusted within 
any given range. In the experimental model 
the ampltitude over the whole range was constant 
to within better than 2%. 

If it is desired to extend appreciably the 

upper frequency limit of the oscillator, Tr3 

should be changed to an OC41. This modification 

allows the oscillator to work satisfactorily up to 

— continued on page 335 




PRACTICAL WIRELESS 



337 




CLEAR 
PLASTIC 
PANEL 
METERS 

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quality, 

Moving 
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meters, available ex-stock. 
S.A.E. for illustrated leaflet. 
Discounts for quantity. Avail- 
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l :l /33* n - square fronts. 
=0 HA 32/8 1A. DC 22/8 

lOOnA 39/6 5A. DC 22/6 

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50-0-50iaA 39/6 50V. DC 32/6 
10Q-O-100[JLf\ 27/6 100V. DC 22/fl 




1mA 

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10mA 

50mA 

100mA 

150mA 

200mA 

300mA 

500mA 

750mA 



22/6 150V. DC 22/6 

32/6 300V. IX' 22/6 

22/6 500V. DC 22/6 

22/6 750V. DC 22/6 

22/6 15V. AC 2276 

22/6 50V, AC 22/6 

32/6 150V. AC 22/6 

22/6 30nv. AC 22/6 

22/6 500V. AC 22/6 
23/6 



Type MR. o-'P. Si' nq. front. 



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50 y. A 
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VU Meter 59/8 300V. AC 35/- 
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All others 



ILLUMINATED 'S' METER 

1 21/32ln. sq. front. Cal. In S 
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MORE METER BARGAINS 

10OU.A 6in. Flush sq. 92/6 
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3!}-0-30mA 2Hn, 9/6 

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M1NIFLEX~* TRACK TAPE HEADS 
Set of three, record, playback, 
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MAINS MOTORS 220 240V 
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Send 1/- P.O. for full catalogue 
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Open 9 a.m. to 6 p.m. Every clay, 
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TS.76 20.000 O.P.V, PUSH 
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fully tested and guaranteed. 
£25. Carr. 30/-. 



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DOUBLE-BEAM 
OSCILLOSCOPE 

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338 



PRACTICAL WIRELESS 



August 1964 



| iinikiiai I 



1 S 

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1 A 

1 A 

I CONCRETE 

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1 



MGLE SPEAKER 



rf ~~ 




An inexpensive col- 
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structed from a 
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fitted with a good Sin. 
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tracted much interest 
and admiration 
because of its clean 
open sound. 
Complete kits of 
wooden fixtures are 
available including 
absorbent wadding 
and diffusing cone. 



i 

i 

SNy UUU1 UII1- 

5^ and 17/6. 

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'" '•• ■:■. : 



Price £3.15.0 for 8" model. Recommended 
8" unit—Super 8/RS/DD £6.14.2 including 
purchase tax. 

Price £4,18.0 for 10" model. Recommended 
10" units— Super 10/RS/DD £10.18.8; Golden 
10/RS/DD £7.17.5; 10" Bronze/ FSB £4.12.9. 
Prices include purchase tax. 

Suitable concrete pipes can be purchased 
from builders' merchants at about 



DescriptiV* leaflet free on request from : 




WHARFEDALE WIRELESS WORKS LTD. 
IDLE BRADFORD YORKSHIRE 

Grams: Wharfdel Bradford 
Phone: Idle 1235/6 



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Pie ase send 3d. stamp for new coil list 

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the big name in PRECISION components 
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BALL DRIVE DIAL 

A welcome addition to our 
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retail price 18/9. 



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is Ball Drive Dial is used in the 3 transistor S.W. converter 
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KINGS WAY- WAD DON, CROYDON, SURREY 
Phone: Croydon 2754-5. Grams: Walfilco, Souphone, London 



August, 1964 



PRACTICAL WIRELESS 



341 



END FED AERIALS 



THEORY AND PRACTICE 



AS the author has several acres available for 
aerials, it is natural that many end fed wires 
have been tried. This type of aerial is simple 
and can work effectively on several bands. It is 
hoped the details following will be of use 
especially to those who are awaiting their trans- 
mitting licences, and wondering what kind of aerial 
to erect. 



may provide 
on the h.f, bands. 



Advantages of the end fed 
aerial may be summarised 
briefly — the same aerial may be 
used on all bands, the length is 
not critical, it is inexpensive 
and often easily erected, and 
some gain over a dipole 

Its main disadvantages are an increase in 
receiver static when conditions are poor, and its 
tendency to cause TV interference, especially 
when incorrectly coupled to the transmitter. With 
correct coupling, TV1 should not be exceptionally 
troublesome. 

Materials 

Hard drawn 14 gauge copper wire is generally 
used, and may be obtained in any suitable length. 
Enamelled wife is preferable, to reduce the surface 
losses eventually likely from oxidization of bare 
wire. Stranded 7/26 wire, with weatherproof 
covering is available in coils up to 100ft. The 7/26 
wire is cheaper and lighter than 14G. and no 
reduction in aerial efficiency was apparent when it 
was used. Necessary joints were made by twisting 
the wire together for about 2in., soldering, and 
painting with bitumen. 

One 3tn. ribbed glass insulator can be used at 
each support point, or a pair, if available. The 
polythene line sold for aerial erection is ideal 
between insulators and supports, though any thin 
strong cord, for outdoor use, would be suitable. 



by F. G. Rayer 
G30GR 



With an end fed aerial, the transmitter end is 
usually supported at the house. The line should be 
taken to the highest possible point, and is of such 
a length that the down-lead is at least 2ft. from 
the walls for most of its descent, as in Fig. 1. In 
many cases the whole aerial can be a single, uncut 
wire. Its length is made up by the horizontal top, 
down-lead, and connection to the transmitter or 

tuner. That is, from A to B in 

Fig. I. 

Only one other support is 
required, again as high as can 
be arranged. It may be possible 
to take a line to another building, or to a tree, or 
to a pole fitted vertically in a tree, or attached to a 
building. Or a 6ft. 4in. x 4in. or similar post mav 
be set in the ground, and the pole may be bolted 
to this. 

If the line is run through a spare insulator 
attached to the top of the pole, it will be easy to 
raise or lower the aerial, or adjust its tension. 

Harmonic Working 

The lowest frequency at which the aerial is a 
i-wave long is its fundamental frequency, and 
multiples of this frequency are harmonics. In 
Fig. 2, the aerial is a ±-wave long for 40 metres. 
Current is nearly zero at each end. and reaches a 
maximum in the centre. Voltage is at a maximum 
at each end, and low in the centre. 

If the aerial were used for 20m. it would 
accommodate two t-waves, as at B. If used on 
10m, the length would be four i-waves, as at C. 
The length of wire for a -J-wave aerial may be 
found from the following, the result being in feet : 

468 




Aerial 



Ribbed insulators 
Pole or other support 




Frequency in Mc/s. 

The lengths thus found are 
0-95 of a |-wave in free space, 
to allow for end effects. A length 
near the centre of an amateur 
bitnd is sufficiently accurate for 
the whole band. Suitable ^-wave 
lengths are : 



Fig. / : Typical end- fed aerial system. 



l-SMc/s band 
3-SMc/s „ 
7Mc/s 

l4Mc/s 

21 Mc/s 

lOMc/s 



246ft. 
128ft. 

66^ft. 

33ft. 

22ft. 

I6ift. 



342 



PRACTICAL WIRELESS 



When the aerial is operated upon harmonics, 
end effects only apply to one i-wave. As a result, 
the aerial length is more nearly that of the number 
of i-waves in free space. For harmonic working, 
the length is easily calculated as follows : 
492 X (No. of i-waves — 005) 

Frequency in Mc/s 
As example, suppose an aerial is four ^-waves 
at 21-2Mc/s, The length is: 
492 (4 - 005) 

=9 1.7ft. 

21-2 



Feed Impedance 

If the aerial is a i-wave long, or any multiple of 
i-waves, as in A, B or C, Fig. 2, high voltage but 
low current will be present at the end connected to 
the transmitter or tuner. The feed point (end) will 
thus be at high impedance. The actual impedance 
can easily be 1,000ft, or higher. 

Should the aerial be only long enough to be a 
$-wave, as at A in Fig. 3. low voltages but high 
currents will be present at the transmitter end, 
which will thus be low impedance. In these 
circumstances, the feed point impedance may be 
50ft or even less. 

When the aerial is some intermediate length, 
such as at B in Fig. 3, its feed point impedance will 
also be some intermediate figure. The feed impe- 
dance will also be of some intermediate value when 
the aerial does not accommodate an exact number 
of i-waves, at some harmonic frequency, as at C 
in Fig. 3. 

It is thus apparent that provision must be made 
at the transmitter to operate into a wide range of 
impedances. This can be done by using a pi-output 
tank circuit, or an aerial tuner. The latter is often 
preferable, because it allows the whole aerial 
system to be tuned to resonance, and helps 
suppress TVL 

Aerial lengths 

Methods of calculating the length for funda- 
mental and harmonic use have been given. The 
length of the aerial will also help influence the 
gain (if any) which the end fed aerial will have 
over an ordinary ^-wave dipole. 



Low Impedance — »-•- 



Current 



(A) Ja wave aerial 



s=: 




<B) Appro*. 3& wave aerial 
(C) Jfe wave aerial 



Fig. 3: Current in odd-fength oeriafs 



L. 




(A) 7M0 (40m) 



-Voitage 




(B) 14Mc/s (SOm) 



Current" 



(C) 28Mc/s (10m) 

Fig. It Fundamental and harmonic operation, showing 
distribution of current and voitage. 

When the aerial is sufficiently long to accommo- 
date a number of ^-waves, the strength of the 
signal radiated is increased in some directions. The 
power gain, for aerials of several i-wave lengths 
long, is approximately as follows; 



No. of^-waves 


Gain in dB 


4 


1-5 


6 


2*3 


8 


3-2 


10 


4-2 


12 


5 



As example, suppose the aerial is 138ft. long. 
This could be used as a i-wave on 160, and a 
•J-wave on 80m. It would be two ^-waves on 40. 
On 20m. it would be four |-waves, with l\5dB gain 
over a dipole. On 15m, it would be six ^-waves, 
with about 2-3dB gain, and on the 10m. band it 
would be eight |- waves, with a gain of just over 
3dB. 

When the aerial is fairly long, useful gain is 
obtained. It is generally found that the aerial is 
also a good radiator in other directions. For 
general purposes, lengths between about 90ft. and 
246ft. have all been found effective. The directivity 
and increased gain are most likely wanted on the 
14 and 21 Mc/s bands, and suitable lengths for 
these are as follows: 

l4Mc/s Two £-waves, 68ft. Three |-waves, 
103ft. Four £-waves, 138ft. Six ^-waves, 207ft. 

2IA1c/s Two l-waves, 45£ft. Three £»waves, 68ft, 
Four i-waves, 91|ft. Six^-waves, 137ft. 

Some lengths will be a multiple of |-waves on 
several or all bands. For example, 138ft. is suitable 
for 3-5, 7, 14, 21 and 28Mc/s. In experiments 
between G30GR and Capetown, reliable contact 
was maintained with an aerial six £-waves long, 
when attempts to cover this distance with a dipole 
had failed. When space is limited, 68ft. is useful 
for 7, 14, 21 and 28Me/s bands. 

Intermediate, odd lengths can be worked success- 
fully provided the method of feeding the aerial is 
adjusted to suit. This is best done by using an 
aerial tuner. It is then not even necessary that the 
length is known, though this information can be 
useful. 



Auguir, 1964 



PRACTICAL WIRELESS 



343 



Directivity 

When the aerial is about 4-wave long at the 
working frequency, there is little directivity, 
though radiation is best at right angles to the wire. 
When the wire is two j-waves long, strongest radia- 
tion is at about 54 degrees to the aerial. For three 
i-waves, the best radiation is at about 44 degrees 
to the wire, and for four $-waves the angle is about 
36 degrees. The angle is about 28 degrees for six 
i-waves, and 17 to 18 degrees for eight |-waves. 

It will be seen that radiation is more and more 
nearly in line with the wire, as the number of 
4,-waves is increased. For example, the 138ft. 
aerial would have lobes at 54 degrees on 7Mc/s, 
36 degrees on 14Mc/s and 28 degrees on 21Mc/s. 

This increased radiation may be pictured as a 
cone extending away from the ends of the wire, 
and the angles given are for radiation at approxi- 
mately horizontal levels. At angles above and 
below the horizontal, the radiation is more nearly 
in line with the wire, when plotted on a map. 

The aerial can thus give good coverage in 
directions other than those favoured by the angles 
of the four lobes in a horizontal plane. In 
addition, much of the low angle radiation obtained 
is extremely useful for long distance working. If 
it is wished to know bearings, these must be taken 
from a globe or great circle map. 

Fig. 4 shows a wire four $-waves long, with 
main and secondary radiation lobes. If the same 
wire were used on one-half the frequency, it would 
then be two i-waves, and the lobes for this are also 
shown. 

Atrial Feeding 

The down-lead is brought into the house by 
means of an insulator or tube, insulation being as 
good as possible. A detachable earthing clip, or 
earthing switch, may be fitted here. 

In some cases the aerial can be fed directly from 
the transmitter. If the transmitter has a pi-output 
circuit, such as that in Fig. 5, the aerial is taken to 
the tank coil at C2, as shown, C2 (usually a 2-gang 
or 3-gang 500pF capacitor) is fully closed, and the 
tank is tuned to resonance by CI, 



Directional lobes 

of aerial 
two 1£ waves long 



Directional lobes 

of aerial 

four 1 /fc waves long 




Fig, 4: Directional lobes at 2-waves and four %-waves. 



RFC 




<5> 



Anode current meter 



ft 



Tank coil 



FA 



<y 



set 



(2x500pF) 



HX.+ 



Aerial 
— — O 



Fig. 5 (above) i Typical pl*output circuit. 
Fig. 6 (below): Tuner arrangement for end-fed aerials. 



Transmitter 



*— £ 




Resonance is indicated by a dip in anode 
current, as read on the meter, If the anode current 
is too low, C2 is opened slightly, and CI re-tuned, 
this being repeated until the valve is drawing its 
expected anode current. 

If the aerial impedance is very high, C2 will 
have to be opened very much, and the voltages 
developed will be high. In these conditions. C2 
may spark over. If so. an aerial tuner is needed. In 
other cases, the setting of C2 for correct loading 
may make it impossible to tune the tank to 
resonance with CI. An aerial tuner will also avoid 
this. 

When C2 is at a relatively low value, as it must 
be with a high impedance aerial, harmonics are 
more likely to reach the aerial itself, thus causing 
TVI. An aerial tuner will then also be of benefit. 

If TVI does not arise, and if the transmitter can 
he loaded properly by the aerial then the latter 
is directly connected, then Fig. 5 may be used. But 
if there is insufficient loading, sparking over, or 
other troubles, some kind of aerial tuner is 
required. 

Tuner 

Any ordinary aerial tuner will be suitable. A 
circuit is shown in Fig. 6. and may be easily 
constructed in a separate case. The coil LI is tuned 
to the operating frequency. For 3-5— 28Mc/s. 26 
Turns of ISs.w.g, wire, on a former 2£in. in dia- 
meter and 5in. long (e.g., Eddystone 10*90) will be 

— continued on page 378 





455 



460 



465 



470 



475 K( 



IN recent years the Q-Multiplier circuit has 
been widely used as a cheaper and more 
flexible method of varying selectivity than the 
crystal filter. 

Most Q-Multipliers are in the form of an " add- 
on *• unit employing a single or double triode and 
have the advantage of requiring no modification to 
the circuit of the receiver with which they are used. 
On the other hand, they have the disadvantage 
that either room for them has to be found within 
the receiver cabinet or an entirely new unit has to 
be constructed. 

■ This article describes two extremely cheap Q- 
Multiplier units which can be formed by simple 
modification to an existing stage of any superhet 
Teceiver and which require an absolute minimum 
of . additional components. Before discussing the 
new circuits, a word about " Q ", which is a 
measure of the efficiency of a circuit or 
component 

Circuit Inefficiencies 

^ If the capacitor C, in the simple oscillatory 
(circuit (Fig. 1) is charged, it will discharge through 
ithe coil L. In doing so, it will produce an e.m.f. 
(which tends to charge the capacitor up again. This 
(having occurred, the capacitor will discharge again 
and the whole cycle is repeated. 

In theory this oscillation would go on ad 
infinitum. In practice, of course, it soon dies away 




Fig. I (left): A simple oscillatory circuit. 

fig. 2 (right): A simple oscillator. Energy for the anode 

circuit is fed back from the coupling coil 12 into the basic 

escillatoryScircuit (LI and C) thereby maintaining 

continuous oscillation. 



due to inefficiencies in the coil and the capacitor 
and, more particularly, due to the resistance of the 
circuit. (This is analogous to the decay of a pendu- 
lum swing due to air resistance and friction in the 
bearings.) 

If the losses in the oscillatory circuit can be 
made good, the circuit can in fact be made to 
oscillate continuously. Thus a simple oscillator 
can be made up as in Fig. 2. A coupling coil from 
the anode of the valve being used to feed energy 
back into the oscillatory circuit. 

Similarly, if a tuned circuit is used in an ampli- 
fier it is also subject to losses affecting its perfor- 
mance. In theory, the circuit responds only to one 

1 
frequency determined by the formula i= -. 

In practice, due to inefficiencies, it allows frequen- 
cies either side of the theoretical one to _ pass 
through it. although to a lesser degree. The circuit 
has bandwidth (i.e. a band of frequencies which 
will pass through it) and its response may be 
shown graphically as in Fig. 3. 

Bandwidth 

Some degree of bandwidth in a receiver is, of 
course, essential since, owing to its information 
content, the received signal occupies a certain 
width of the r.f. spectrum. For reception of 
musical programmes a total bandwidth of lOkc/s 
might be regarded as essential. For speech only 
this could be much reduced and for c.w. 200c /s 
could well be adequate (or, indeed, essential if the 
desired signal was adjacent to unwanted powerful 
signals). 

Thus, assuming that most receivers have a fairly 
wide bandwidth suitable for reception of music, 
we see that this bandwidth can be reduced if 
necessary by increasing the efficiency of the tuned 
circuits of the receiver (Fig. 3). And we have also 
noted that the efficiency of a tuned circuit can be 
improved by feeding energy back into it, thereby 
increasing (or multiplying) its " Q " value. 

The simplest possible Q-multiplier can be 
formed, therefore, by connecting a small capacitor 
between anode and grid of one of the i.f. ampli- 
fier valves of a superhet receiver. Such a modified 
stage is shown in Fig. 4. Additional components 
are shown dotted. 



I . 



MULTIPLIERS 



by P.R.LEWIS 



Improving selectivity without a crystal filter 



The capacitor Cx provides feedback to the grid 
circuit and in practice can be formed by a short 
length of stiff wire soldered to the anode pin and 
bent over towards the grid pin of the valveholder. 
If not already present the gain control VR1 must 
be added to provide control over the stage gain 
and therefore over the Q multiplication. 

In this particular application the stage cannot 
be allowed to go into oscillation. (If this happens 
it is because the feedback is cancelling out all 
losses, the Q is infinite, the bandwidth nil and the 
circuit is useless as an amplifier.) 

Improving Stability 

In practice, therefore, it is desirable to adjust 
the feedback so that the circuit only just goes into 
oscillation when VR1 is at the top of its track. It 
will be found necessary to keep the gain control 
turned well down until the required station has 
been accurately tuned. The gain control is then 
turned up to a point just below oscillation when 
the effective Q is as high as can be obtained with 
this simple circuit. 

As gain is increased, music or speech will sound 
" boxy ", indicating a narrowing bandwidth and 
adjacent interference will be much reduced. The 
margin between high Q and oscillation with this 
basic circuit is very fine, however, and its uses are 
therefore limited. 

A more stable configuration is shown in Fig. 5, 
just a few extra components being necessary to 
improve the perfarmance enormously. The main 
change is that by substituting two series capacitors 
for the original capacitor in the second i.f.t. anode 
coil, and earthing their centre point, it is possible 




l 460 465 470 

kc/s kc/s kds 

Frequency 

Fig. 3: Theoretical response of a circuit tuned to 465 fee's 

only. The dotted lines show the improvement which might 

result if the Q of the circuit is increased. 



JJvXJL 




Frequency 

changer 



0'05uF 



HX+ 



CMjjF 



J 100 
:kfc 




A-V-C, 



Fig. 4: A simple Q-muliplier circuit, using capacitor 
feedback between output and input tuned circuits, and 
incorporated in a typical i.f. stage using an EF93 or 
similar yariable-fj. pentode. Additional components are 
shown dotted, for value of Cx, see teJct, 

to feed back to the grid circuit only a proportion 
of the signal developed across the anode circuit. 

This, together with the introduction of a radio 
frequency choke, makes for much better control. 
The feedback capacitor Cx is nominally 5pF but 
should be adjusted as before until the circuit just 
goes into oscillation at the top end of VR1. 

Note that it is desirable to disconnect the a.g.c. 
line and use a straight r.f. valve (EF95) instead of 
the original variable p. valve, although this latter 
is not absolutely necessary. 

Fine Tuning Control 

An interesting innovation is the tuning capacitor 
VCt. which may be fitted if there is room on the 
chassis. This enables the frequency of the tuned 
circuit to be varied by ±5kc/s from the nominal 
465kc/s, thereby permitting investigation of the 
passband of the receiver without altering the main 
tuning control. 

This method is considered to be a more effective 
method of fine tuning than the more normal band- 
speed control. The receiver may be tuned over an 
amateur band with VR1 turned down and the 



! 



346 



PRACTICAL WIRELESS 



August, 1964 



position of and interference 
between various stations noted. 
VR1 can then be turned up to 
isolate one transmission and, by 
tuning back, over the band with 
VCI, previously heard trans- 
missions may be picked out in 
isolation. If VC1 is fitted the 
lead from it to the anode pin 
should be screened. 

When this type of modification 
is made to the i.f.t. the core will 
need to be accurately realigned. 
A weak but steady transmission 
should be tuned in with VR1 
turned well down. The core 
should be adjusted for maximum 
signal and then VRI gradually 
turned up, adjusting the core all 
the time. The most important 
thing to check whilst doing this 
is that the original transmission 
is retained since, with the 
increasing Q multiplication, it is 
very easy to move on to another 
transmission. 

Finally, Fig, 6 illustrates 
another type of feedback 
arrangement in which alterations 
are made to the input circuit of 
the stage. Once again a.g.c. is 
disconnected from the stage and 
a straight r.f. valve used. 

This type of amplifier provides a very stable 
system (i.e. the margin between high Q and 
oscillation is not so 'critical as in the other circuits. 
Once VR1 has been set to its highest possible 
position the circuit is not likely to go into oscilla- 
tion spontaneously). 





Fig, St An i.f. stage modified to form a Q*muttipller unit, feedback being 

by capacitor Cx from output to input tuned circuits. Values of VCI, C3 

and C4 are calculated on the assumption that the original i.f.t. capacitor 

was lOOpF. If VCI is not fitted, C3 and C4 should both be 200pF. 



Fig. 6: An i.f. stage modified to form a high 'stability low gain Q-muitiptier 

unit. The stage is operated as a cathode follower and a portion of the 

output is fed back via VRI to the input tuned circuit. 

**Q" multiplications of over 150 are obtainable 
(i.e. the Q of the stage may be 15,000), the only 
disadvantage being that the stage gain is less than 
unity. The circuit is thus best incorporated into 
a multi-stage receiver, in which case the modified 
stage should be the earliest possible one after the 
front end. 



Mechanical Construction 

It should be borne in mind 
that in both the circuits of Figs. 
5 and 6 the object is to achieve 
a carefully controlled feedback 
of energy. Therefore precau- 
tions must be taken to prevent 
unwanted feedback. 

The two series capacitors 
replacing the original i.f.t. 
capacitor must be situated in the 
can. The tuning capacitor should 
be screened if possible and, as 
mentioned in Fig. 5, the lead 
from VCI to anode should be 
shielded. 

In Fig. 6 the leads from the 
centre point of the capacitors C3 
and C4 to VCI, from VCI to 
VRI and from VRI to the valve 
cathode pin should all be 
screened, as should the input 
lead to the grid. VRI itself 
should be shielded or, if in metal 
case, the case back should be 
earthed. 



August, 1964 



PRACTICAL WIRELESS 



347 



VIBRATO 



PRODUCING THE TRUE MUSICAL EFFECT 
FOR ELECTRICAL INSTRUMENTS 

BY J. HOLDEN 



MANY of us who enjoy the fascinating pastime 
of electronic music have many times wished 
for a simple device that would produce a 
true vibrato and not, as is so often found in pub- 
lished circuits, amplitude modulated tremolo 
which is to say the least disappointing. 

It is well known that the most successful vibrato 
to date is the Hammond Line Vibrato, which, of 
course, is used on the Hammond organs, and is 
accepted by most organists to be the most out- 
standing feature of these instruments. In fact, 
records made on the old organs which had ampli- 
tude modulated tremulants sound " thin " and 
artificial. 

The Line Vibrato consists of a complicated 
electronic circuit comprising many chokes and a 
large number of capacitors, also a high- precision 
scanner which would be practically impossible to 
duplicate without special tools. 

The following circuit effectively does the same 
job as the above, but only requires the ordinary 
parts that are found in most junk boxes. It consists 
of an inter-valve transformer with centre- tapped 
secondary, ratio approximately 1 : 3 primary to 
secondary — Fig. 1(a). 

The centre tap of the secondary in conjunction 
with a 50kH resistor is the output to main ampli- 
fier, and should be followed with not less than a 
potentiometer of lmft. One side of the secondary 
is connected to earth through a 500kO resistor. 

The other side of the secondary is connected to 
earth through a variable capacitor of approx. 
OOOl^F; this is made up of two sections of a 
tuning gang of 500pF per section, the two sections 
being connected in parallel. 

This variable capacitor is driven by a small 
electric motor at approximately 5-7 revs, per 
second: this causes the signal to be effective across 
firstly one half of secondary, and then as the gang 
attains its maximum capacitance the signal is 
effective across the section connected to this 
capacitor. 

Now it will be seen from the above, without 
going into the matter too technically, that we have 
obtained a phase change which at its maximum is 
nearly 180°. A change in phase is heard by the 
listener as a change in frequency so long as the 
phase is constantly changing. 

The idea of phase change vibrato is not new and 
various devices have been published, but all have 
used valve methods of changing the phase which 
always results in a " thumping ™ sound being 
added to the original signal: all the above devices 
are fitted with filters to remove this "thump", but 
in doing so the signal has to be very much attenu- 
ated at the lower end with the result that the final 
sound is poor. 

The system we are discussing requires no filters 



whatsoever and the frequency range is entirely 
dependent on the quality of the transformer. It 
must be stated at this point that the same effect of 
phase change can be obtained by replacing the 
fixed 500kfi resistor with one of the new light 
sensitive variable resistances, such as ORP60 
cadmium sulphide cell. In this case the variable 
capacitor is replaced by a fixed capacitor of 
OOOI.uF— Fig. 1(b). 

The change of resistance is brought about by 
cutting off and on the light from a small dial bulb 
placed in front of the sensitive portion of the 
ORP60. This can be done by a piece of suitably 
shaped card rotated by a small motor. 



H.T+250V 



input 
from 
organ 




Interrupted 
light ray 



Fig. I (a) and (/>); The two versions of the circuit required 
for producing a true vibrato effect. 

Both methods have been tried out for long 
periods with complete success and no fault has 
been found whatsoever, both on the writer's own 
home-made organ and a commercial modeL viz., 
Polychord. 

The variable capacitor used is the type fitted to 
most all-dry portables, but must be of construc- 
tion that will allow the vanes to complete the full 
circle: the small piece of paxolin which is fitted to 
the ends of the vanes has to be carefully removed. 
Do try not to distort either the moving or fixed 
vanes. ■ 



348 



PRACTICAL WIRELESS 



August 1964 




by M.A.aUALES 



EVERY home constructor must have suffered 
the frustration of seeing his laboriously built 
equipment disparaged because— in the words 
of the critic — it has " an amateur finish ". Useless 
to argue that you are getting umpteen distortion- 
less decibels if the distaff side has sniffed : " All 
those wires and things! " The only answer would 
seem to be a course on basic carpentry, followed 
by a study of polishing techniques. 

There is no need to be discouraged; nor is it 
necessary to take such drastic steps. The amount 
of carpentry that the radio enthusiast needs to 
undertake will be quite small. This is not the place 
to discuss it at any great length. For any reader 
who wishes to follow the subject further, a regular 
subscription to Practical Householder is to be 
recommended. We are more concerned, at this 
point, with the art of the " finishing touch ". 

Whether one is merely repairing the damage 
from a careless cigarette or polishing and finishing 
a complete set of equipment enclosures, there are" 
some basic factors to consider. First, the method 
of work is determined by the material. 

WOOD CABINETS 

Most cabinet work is carried out in wood — 
which is rather like saying that every day is a 
weekday except Sunday! But there are many types 
of timber, and each type has its peculiarities. 
Moreover, the very many veneer and artificial 
finishes available at present give a bewildering 
choice to the constructor. Much depends on the 
required appearance of the piece of furniture we 
are building to house our electronic dreamchild. 

Colour 

The simple and obvious answer would seem to 
be a wood finish left in its natural colour — a trend 
that has had a recent renewal of life in furniture. 
But even this has its drawbacks. No timber remains 
indefinitely the same colour as when it is first cut. 
There is a gradual darkening with exposure to 
light, and as this is a chemical change, the type of 
finish that protects the wood will not prevent this 
natural tendency. 

Any finish will tend to darken the wood slightly; 
a point that must be remembered when matching 
pieces. Whilst it is possible to bleach, it is by no 



finishing • renovating • repairing 



wood • plastics 



means simple, either to carry out, or control. Far 
better to begin with a blonde wood, such as birch, 
in the first instance. 

If it is intended to paint or enamel a piece of 
timber, to obtain the necessary match or to provide 
a certain decorative effect, the softwoods are best 
choices. Fir plywood or knotty pine is a common 
choice. 

Preparation 

Whatever the material, the first essential is its 
preparation. Too often, a neglect of this important 
phase of the work can spoil a finished job, and 
there's no way of overcoming the fault except to 
strip down and start all over. 

Smoothing 

The first thing is to plane and rub down the 
surface until it is smooth. Remember that the small 
groove or excrescence becomes alarmingly visible 
after the decorative finish is applied. This can be 
very noticeable if a high-gloss finish is used, and 
is the reason that some people -advocate the use of 
solid core plywood instead of the cheaper veneer- 
cored types, which may have more of a tendency 
for face veneers to transfer surface ripples from 
the core veneers. 

If a plane is used for preliminary work, a very 
sharp iron and a smooth setting are required, so 
that by sighting along the bottom of the plane, 
only the merest whisker of iron protrudes. Finish- 
ing edges with a plane, especially the edges of 
some plywoods, can be difficult. 

A right-angle block sander can be made, as 
shown in Fig. 1, which takes away some of the 
anxiety. Two blocks of wood are fastened at right- 
angles by shelf brackets, so that a space sufficient 
to take a medium grade sandpaper is left between 
the upper edge of the vertical block and the lower 
face of the horizontal block. The latter is fixed to 
the bracket so that it overlaps an inch or so. 

The glass-paper is fastened as shown, and the 
device allows good edges to be rubbed down 
without the chipping and scarring that often results 
from inexpert use of a plane. 

When sandpapering, use a coarse grade, followed 
by a finer grade, clearing dust with a fine brush 
between sanding operations. (Grades of sandpaper 
vary according to coarseness of abrasive surface — 



Fig. I 
Note 



Augusr, 1964 

the lower the number, the finer the 
particles. Normal grade for this work 
would be No, 2 medium for preliminary 
work, finishing with or 00). The softer 
the wood, the finer the paper. 

Rubbing down of plane surfaces 
should be done with the grain — usually 
along the length of a piece of timber. 
The easiest method of rubbing by hand 
is to wrap the glasspaper around a 
wooden block. Cork is an excellent base 
material for this work, having just that 
amount of " give " that helps toward a 
satiny finish. 



Power Tools 

Nowadays the handyman has a battery 
of powered tools at his disposal, and 
sandpapering can be less of a chore. But 
it should be stressed that some machines 
are quite unsuitable for delicate finishing. 

A rotary sander, for example, must operate for 
part of its travel across the grain of the wood, and 
this is not advisable for the kind of work we are 
considering. Where there are ridges, mouldings, 
etc., it is always better to fashion a block to fit the 
shape of the moulding and rub down patiently bv 
hand. ' 

The importance of this rubbing down — and the 
next point to be mentioned— cannot be too 
strongly emphasised. A good finish will not be 
obtained unless the basic material is quite smooth. 

Small Flaws 

If there are small flaws, cracks or crevices, these 
should be filled. Large holes can be stopped with 
a putty filler, or one of the water-mix powders on 
sale for plaster-filling, or with plastic wood. 

A point to note is that putty has a linseed oil 
base. The oil will soak into the wood as the putty 
dries out and the stopping shrinks. Similarly, the 
powder mixtures dry and shrink, and being softer 
than the basic material will tend to drag from the 
stopping when re-sanded, leaving a noticeable 
blemish. 

Best method of preparation is to impress the 
stopping firmly, leaving it proud of the main 
surface, allowing it to dry (the plaster-of-paris 
mixtures and the newer polymer preparations dry 
out very quickly — too quickly, as one finds when 
too much is mixed at one time!) After this, the 
protruding surface of the stopping is cut down to 
the level of the wood, and the whole surface sand- 
papered until no difference can be felt to the level. 

If the hole to be stopped is fairly big, or a 
crack deep, it may be necessary to make two or 
three stoppings, or the outer skin of the material 
used for the stopping hardens, preventing the 
softer inner core from drying out. 

This is similar to the filling carried out to even 
the roughness of hardwood finishes, preparatory 
to staining and polishing. Depending on the type 
of timber, and the direction of cut that gives it 
the characteristic grain, the amount of rubbing 



PRACTICAL WIRELESS 



349 




: Rubbing block for sand-papering edges of timber. 
gap between blocks to permit easy replacement of 
glass-paper. 



down that can be done will vary. Before taking 
this operation too far, it is necessary to decide on 
colouring and type of finish. 



Basic Methods 

There are three principal methods of finishing 
a hardwood surface: oil polishing, french polish- 
ing and wax polishing. Unless it is required to 
keep the natural colour of the wood, perhaps pro- 
tecting it with a clear varnish or a french polish 
alone, a stain will first be worked into the wood. 

It is often necessary to mach this colouring very 
carefully, and the choice of stain depends upon 
the wood, as well as the effect that is being striven 
after. Although there are three types of stain 
available (alcohol, water and oil-based) it is 
usually the last two which find most popular 
employment by the amateur. 

In general, oil stains do not penetrate the wood 
as readily as water stains. On a hard, or close- 
grained wood, water stain may be quicker and 
easier to use, whereas on soft woods, such as pine 
or fir, oil stains may be easier to control for colour 
matching. 

Water stains are usually supplied as crystals, 
mixed as you require, but oil-based, or naptha- 
based stains are more often ready mixed. A cheap 
water stain can be made by dissolving crystals of 
potassium permanganate in water. 

Using a water stain requires patience. A little is 
applied at a time, until the shade you require has 
been achieved. Application tends to raise the grain 
of the wood, and it is often necessary to rub down 
again after it has been used. 

Oil stain is laid on fairly quickly with a well 
loaded brush, to cover the whole work, then sur- 
plus stain wiped off until the right shade is 
obtained. If the wood is porous, it will be 
necessary to wipe off fairly quickly to keep the 
tone even, especially on a surface of any 
appreciable area. 

Care must be taken when staining the end grain 
of a workpiece, as this is more porous, and will 
soak up the stain more quickly, resulting in a 
darker finish. 



350 



PRACTICAL WIRELESS 



August, 1964 



Grain Filling 

The next stage, after staining, is the filling of 
the grain, A- patent filler can be used, and is per- 
haps a better method for small surfaces, but if a 
larger amount is required, a powder plaster filler 
can be mixed as required. The dampening agent 
for light-coloured surfaces could be linseed oil, 
or a stain of the same colour as the prepared 
surface. 

After staining, and before filling, the surface 
should be rubbed down with a fine glass-paper. 
The object of filling is to level off the ridge-like 
irregularities of the grain, and thus the filler should 
be applied with a pad of rough cloth across the 
grain. 

The usual method is to begin lightly, over a 
small area, working until the powder of the filler 
is used up, recharging the pad until the surface is 
covered, then going back over the surface in small 
sections with a circular movement. 

As the filler commences to dry, change to a dry 
pad and wipe all surplus powder from across the 
grain and at edges and in crevices. After the filler 
is completely hard — usually an overnight process, 
even for the quick-drying preparations — the 
surface can be wiped over with a pad moistened 
in linseed oil. 

This should be done lightly, so as to just form a 
seal on the surface, combining with the powder 
filler. Again, leave the work to dry, then rub 
down with a fine glass-paper, or a worn piece of 
O-grade, finally dusting to remove all loose 
particles of filler. 



Oil Polishing 

Oil polishing is simple to carry out, but it does 
take time. It is absolutely vital that the work be 
left undisturbed between rubbings. 

The oil used is raw linseed oil, and it is worked 
well into the wood by a soft cloth with a firm 
surface, varying the direction of movement of the 
pad as the surface is covered. Between polishings, 
the surface may be rubbed down with a soft brush 
to burnish it slightly. Heating the oil a little 
improves the penetration. 

The finish is attractively "deep", without the 
high surface shine of a hard polish, and re-oiling 
every six months or so is all that is needed to 

maintain the work. 



French Polishing 

French polishing is a different proposition, and 
the beginner would be well advised to practice on 
spare pieces of timber before committing himself 
to- the- precious cabinet he has constructed. The 
work is prepared in the same way as before, with 
the filling done after staining and the surface 
rubbed down with a fine-grade glass-paper. 

There are four kinds of French polish in general 
use, and different qualities of these polishes. The 
types are determined by the shellac used as a base, 
dissolved in methylated spirit. The preparations 



ready bottled are in the right proportions, but the 
professional prefers to mix his own. The following 
notes are intended only as a guide for the con- 
structor who wishes to experiment. 



Finishes 

Garnet polish has a rich, greenish-brown colour. 
It is normally used on dark woods, but may be 
employed to darken the colour of a piece— 
although this needs some experience to achieve 
both a quality finish and a colour match. Six 
ounces of garnet shellac dissolved in a pint of 
methylated spirit gives the correct proportion. 

Button polish is not quite so dark, having a 
golden- brown finish, suitable for meduim colour 
woods. It has a slightly cloudy appearance and is 
rather harder than the other types. Six ounces to 
one pint. 

Orange polish may be used on lightly stained or 
unstained woods, the latter method giving a pale 
yellow finish. Again, six ounces to a pint of spirit. 

White polish is almost colourless, and can be 
used on unstained woods, or where it is necessary 
to preserve the lightness of tone. Eight ounces of 
bleached shellac are dissolved in a pint of spirit. 

The four kinds may be mixed to give inter- 
mediate tones. The shellac should be put in a bottle 
containing the required amount of spirit, tightly 
corked, and left for several days to dissolve, with 
an occasional vigorous shaking to help things 
along. Because of its highly volatile nature, the 
usual precautions against fire must be taken and 
the bottle should always be tightly corked. 

It is a good idea to groove a cork as in Fig. 2, 
and substitute this for the stopper when working. 
This allows a better control of the amount being 
poured, and limits evaporation. A further precau- 
tion is to keep the work well away from any dust. 

If possible, work in a warm dry room, where 
there is likely to be no disturbance; and if it is 
possible to place the work in front of a window, 
the bringing-up of the surface can best be gauged. 



Fadding 

First step is " fadding " with a pear-shaped pad 
of wadding — unbleached — prepared by first soak- 
ing the wadding in the polish, allowing it to dry, 
then making it into the pad shape, pouring just 
enough polish on the pad to wet it, without setting 
up a drip, tapping off any surplus polish on a sheet 
of paper, then applying directly to the wood. 

Fadding seals the timber, giving a good founda- 
tion, and the pad should be worked evenly and 
quickly over the whole surface, with the grain at 
first, taking care to overlap the edges so as to 
prevent the building up of light-catching ridges at 
later stages of polishing. When the first rubbing 
has dried and hardened, it should be sanded-down 
with a grade-O glass-paper, then well dusted. 

This operation should be repeated several times. 



August:, T964 



PRACTICAL WIRELESS 



351 



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352 



PRACTICAL WIRELESS 



August, 1964 



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August, 1964 



PRACTICAL WIRELESS 



353 



building up the base of protective polish. The 
spirit dries out in a few minutes. 

Next step is to oil the pad with either a white 
mineral oil for light pieces or boiled linseed oil 
for darker wood. Only a small amount of oil is 
applied to the work surface to act as a lubricant, 
while the polish is used to dampen the pad as 
before. 

As the pad becomes dry, recharge with oil, work- 
ing always with small amounts, and covering the 
whole surface with a sweeping figure-of-eight 
movement, and the edges with small, regular 
circles or loops, so that the whole work is covered 
evenly. Fig. 2 a and b. 

When this operation is concluded, view the sur- 
face toward the light to make sure that no irregu- 
larities remain. Then leave to harden and rub 




Fig. 2: Rubbing movements for polishing: (a) fadding; 
(b) loop pattern to cover whole surface, used in tatter stages 
of fadding and first stages of rubbing — the small outer 
loops carry the polish right to the edge; (c) broad, light 
sweeps in last stages of rubbing, gradually straightening 
as the polish becomes harder. 



down with OO grade glass-paper, carefully remov- 
ing all dust with a soft brush. 

Bodying 

After oiling, " bodying " is carried out; this is a 
build-up of several layers of polish, and again, oil 
is used to lubricate the rubber, which is made of 
a piece of white linen over a pad of unbleached 
cotton wool. 

First stage of the bodying is a straight back- 
wards and forwards movement of the rubber, lift- 
ing it cleanly at the ends so as not to scrape the 
edges, and using a very light touch, As the surface 
begins to gleam, recharge the rubber and change 
the directional movements, using long sweeping 
loops. Fig. 2c. 

Do this several times, after each operation 
leaving the work to harden for 24 hours between 
rubbings. 

Spiriting- off 

The final process is " spiriting-off " with a 
rubber half-charged with methylated spirit and 
half with polish. This rubber is taken over the 
surface in a series of oval movements which 
graduate to straight strokes as in Fig. 2c. 

Reduce the polish content with each application, 
until the last rub is made with a rubber completely 
charged with methylated spirit only (but take note: 
very lightly charged). 

This burnishes the surface, which can be rubbed 
over afterwards with a soft cloth, dusted with 
Vienna chalk. 



Wax Polishing 

Wax polishing is comparatively simple. A polish 
can be bought ready-made, or prepared from a 
mixture of beeswax and turpentine. Dissolve 4oz. 
beeswax in -| pint turpentine, cutting the wax into 
thin slivers and allowing the mixture to stand until 
the beeswax dissolves. 

The process is accelerated by heat, but care 
must be taken not to ignite the polish. Colouring 
is adjusted by adding dry powder colour to the 
turpentine before the wax is shredded into it, then 
decanting the turps into another container through 
a fine mesh cloth strainer. 

The polish can be applied quite vigorously, and 
as many times as required, until a gleam in? 
surface is obtained. 



RENOVATING WOOD CABINETS 

This is all very fine for the new piece — that 
virgin cabinet with the flawless surface — but more 
often we are concerned with ** touching-up " 
operations, and here there may be several short- 
cuts. 

Various scratch removers, stains and retouching 
polishes are available, and sticks of shellac are 
readily obtainable, A rubbing compound is a use 



354 



PRACTICAL WIRELESS 



August, 1964 



ful finishing aid. Minor scratches, which result in 
a '* tired " look, can be quickly polished out with 
a rubbing compound used on a gloss finish. For 
the satin finish, or dull sheen look, a pumice and 
oil is more suitable, or even fine steel wool. 



Deep Scratches 

Deeper scratches require individual treatment. If 
the chipping or scratching lies deeper than the 
polish, burning in or French polishing will be 
needed. First, the damaged area must be cleaned 
up, any loose chips or splinters removed, and the 
rough edges stained for a colour match. 

Then, the application of a shellac stick, with a 
little heat applied from an alcohol lamp or heated 
palette knife is employed to fill the depression, 
finally smoothing out the protruding shellac, 
rubbing down and polishing as described before. 



Shallow Scratches 

If the mark is wide but shallow, it may be 
preferable to French polish with white shellac, 
rubbing the shellac and spirit mixture with a fairly 
well damped pad into the depression, gradually 
building np the level until it matches the surround- 
ing surface, then spreading the polishing area to 
obtain an even finish. 

This requires "a little practice, but can give 
excellent results. Even bad-looking burns can be 
camouflaged by this method — but it should be 
remembered that burnt or charred wood must be 
scraped away before the polishing begins, or it 
will leave an eventual discoloration. 



St&liw 

Water or beverage stains — those annoying rings 
that remain after the party has broken up— are 
often quite shallow, and will succumb to judicious 
rubbing with steel wool or pumice. If stubborn, 
the stain may be treated with a pad lightly damped 
with ammonia, brushed lightly over the affected 
area. Lacquer finishes require a touch of lacquer 
thinners, but great care must be taken not to 
remove the actual polish, or the end result will be 
a complete polishing job. 

It is extremely difficult to "patch" this kind 
of work, and a careless rub may mean completely 
removing the finish and starting again — if you will 
pardon the pun — from scratch ! 



PLASTIC CABINETS 

Plastic cabinets require a different treatment. 
Scratches are often quite easy to deal with. The 
colour of the material is the same all through, so 
that removing scratches is usually a matter of 
polishing them out with a flatting paste and metal 
polish. 

To minimise the effect of the slight depression 
\ Ifcat is noticeable on a flat surface where a smalt 



Self tapping 
screw 




Pillar with 

threaded 

hole 



Fig. 3: 



Method of overcoming worn threads in plastic 
cabinets and mountings. 



area has been polished, simply extend the polished 
area. Quite deep scratches can be dealt with this 
way, needing only the application of metal polish, 
elbow grease and a modicum of patience. 

Methylated spirit is a useful cleaning medium 
for soiled plastic cabinets. The dull smear that it 
leaves as it evaporates is easily polished away with 
a dry cloth. But care must be taken, when using 
methylated spirit, or even warm water and house- 
hold detergent, which can be effective, if messy; 
the danger is that painted or teaf-painted lettering 
will rub off. 

It may be necessary to mask the area of letter- 
ing, cleaning the main body of the work, then 
treating the small spaces around the lettering indi- 
vidually with a rag around an orange-stick, or 
even a fine paint-brush. 

Dust 

A film of dust rapidly builds up on plastic 
surfaces left unattended. Much is due to electro- 
static attraction. A good cure is a rub over with an 
anti-static preparation, or a wipe with a record- 
cleaning cloth— several of which can be obtained 
on the open market. 

Never use a dirty cloth for polishing wood or 
plastic, and always keep the cloth in a paper or 
plastic bag when not in use. 

Deep Scratches 

Particular problems are deeper scratches, broken 
knobs, and dirt in ridges and milled edges. The 
latter problem is again a matter of patient cleaning 
— this time with soapy water and a soft nail-brush, 
scrubbed across the ribs of a speaker louvre or the 
milled edge of a knob, toward the open end. 

Take care that the fabric behind a speaker louvre 

does not get discoloured or stretched— it is often 

— continued on page 376 



August 1964 



PRACTICAL WIRELESS 



355 




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This outstanding meter was featured by Practical Wireless in 
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Data and circuit available separately 2/fj refunded If all parts 
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A must for business or pleasure This 
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356 



PRACTICAL WIRELESS 



August, 1964 



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CAN YOU ANSWER THE FOLLOWING 
QUESTIONS? 

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3, Can a ribbon microphone be used out of doors ? 4. Where 
can you buy a |* polythene plug? 5. Where can you buy 130 
different sizes of metal chassis, available in 4 different finishes ? 
6. What is the formulae for the reactance of a coil ? 7, Where 
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connecting tags ? 

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PLEASE WRITE TOUR NAME AND ADDRESS IN BLOCK CAPITALS 



NAME 



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HOME RADIO LTD., Dept, PW, 187 London Rd., Mitcham, Surrey 



August 1964 



PRACTICAL WIRELESS 



357 



on the 

Short Waves 



A MONTHLY COMMENTARY BY J. GUTT Rl DGE 



IF properly kept a log is invaluable to the DX-er. 
From it he can gather together the information 
required when making reports, make notes of 
station schedules and compare conditions on 
different bands so that he can quickly choose the 
best frequency when he wants to tune in again to 
a station. Here then are some notes on the system 
I use, but they can be modified or simplified to suit 
individual requirements. 

I use 17 columns to set down details of a 
listening contact that I require. This is a lot of 
columns to rule up but the amateur radio station 
log book issued by Webb's Radio, 14 Soho Street, 
Oxford Street, London, W.l, can be modified 
easily to fill the bill. 

The first column is for the date. The second 
contains time that listening started and the third 
the time that it finished. To avoid confusion 
always use Greenwich Mean Time and the 24-hour 
clock. The next column gives the frequency of 
the station under observation. This wants to be 
accurate to 5kc/s. 

After this comes the name of the station, 
followed (where applicable) by its call sign. I 
then use a column for the power of the trans- 
mitter. This requires reference to a handbook and 
is not strictly necessary but can be interesting 
when comparing signals from two transmitters in 
the same neighbourhood. 

The next five columns give details of the signal 
being received. I use the S1NPO code, which is 
favoured for reports by most stations (Signal 
strength, Interference, Noise, Propagation disturb- 
ance, Overall merit). Each of these is given a 
mark out of five. More about how to use the 
code next month. 

I then have another column for details of any 
interference (e.g. jammer, c.w,. telephone, S.s.b., 
broadcast), the frequency and, where possible, 
location. 

Because of the format of the log sheet I use 
the next two columns contain the date any report 
was sent and the date a QSL was received. 
Logically these would be the last two columns on 
a drawn-up log sheet. After this comes a column 
indicating the transmitter beam, if any. 

In the final column I record details of the 
programme being monitored. To save this column 
getting too unwieldy you will probably have to 
boil down the information, using your own form 
of shorthand. 



LANGUAGE TUITION 

If you're thinking of learning German or just 
want to pick up a smattering of the language for 
a holiday try the German lessons for English 
listeners broadcast by Osterreichischer Rundfunk, 



Wien IV, Argentinierstrasse, Austria, at 1830 GMT 
on Tuesdays and Saturdays on 6,155kc/s. This 
station is on the air to Europe from 0500 — 2200 
on 6,155kc/s, 0600—2000 on 7,245kc/s, 0900— 
1700 on 9,770kc/s and 0900—1300 on ll,785kc/s. 
This station QSL's and will also supply special 
report sheets. 

A letter to "Dutch by Radio", c/o Radio 
Nederland, PO Box 222, Hilversum, Holland, will 
bring you free of charge full details and printed 
texts for their second series of " Dutch by Radio " 
programmes, due to start in November. The 19m 
band with a standby outlet in the 1 6m band have 
now been added to the 25, 31 and 49m bands for 
this station's 2000 English transmission. This is 
another station that QSL's. 

PROGRAMME CHANGES 

All-India Radio has made some changes in the 
frequencies for its English transmissions from 
1945 — 2045. This is now beamed to the U.K. on 
6,1 30/7,235 /9.915kc/s and to West Africa on 
7,125/9,690/1 l,835kc/s. Best reception is on 
7,235 and 9.915kc/s. A special three-minute 
transmission in connection with the International 
Year of the Quiet Sun gives a chance to hear this 
station in the 75m band on 3,925kc/s. Other 
frequencies used include 4,760/7,270/9.615kc/s. 
Full programme schedules are available from the 
Director of External Services, All-India Radio, 
Post Box 500, New Delhi, India. 

Slight changes have been made by Radio 
Prague, Czechoslovakia. Its broadcasts to the 
U.K. are now from 1200—1230 in the 49 and 25m 
bands and 1900—1930 in the 49 and 31m bands. 

Very good reception of the Spanish programme 
of Radio Warsaw, Poland, from 2030 — 2057 is 
given on the new frequency for this transmission 
of 9,540kc/s. 

Radio Sweden, Box 955. Stockholm I, Sweden, 
has now moved from l,5420kc/s to 15, 445kc/s for 
its 1445 — 1600 transmissions to South Asia. 
Unfortunately this frequency is the same as that 
used to Europe at this time by Radio New York 
Worldwide. Sometimes New York and sometimes 
Sweden come out on top! 

The full schedule (valid until September) of 
Radio New York Worldwide is: To the British 
Isles, 1200—1624 on 11.825kc/s, 1630—1815 on 
11.900kc/s, 1830—2145 on 15,290kc/s; to Con- 
tinental Europe, 1200—1554 on 15.445kc/s. 1600 
—2154 on 15,440kc/s; to Africa. 1200—1815 on 
15,260kc/s. 1830—2145 on 15.290kc/s; and finally, 
to the Caribbean from 1200 — 0000 on I1.940kc/s. 

An African station now giving good reception 
in the 60m band is the home service of Radio 
Ghana. After 1900 it can be heard through the 
c.w. on 4,915kc/s. 



353 



PRACTICAL WIRELESS 



August 1964 



[-Transistor Pre-amp 

WITH TREBLE AND BASS CONTROLS 



by P.K. Cripps 



ANY small transistor pre-amplifiers do not 
provide for any form of tone control, 
and this deficiency has often limited their 
usefulness. The unit to be described offers separate 
control of treble, bass and volume, in addition to 
the pre-selection of one of three alternative input 
sources. 

The Circuits 

After selection by SI, a three-way single pole 
switch, the signal passes to the base of the OC71 
transistor via the volume control, VR1, and the 




bass control, VR2. Base bias for the transistor is 
supplied by the potential divider R1/R2. 

The amplified signal appears at the collector of 
the transistor and is fed across a treble cut control 
circuit VR3/C3 to the coupling capacitor C4 and 
from there to the main amplifier. 

Components 

The three variable resistors should be in good 
condition without worn tracks which could cause 
crackling when their spindles are rotated. 

In the interests of a quiet background, it is 
recommended that resistors of 
half or even one watt rating are 
used. Quarter watt resistors, of 
the type normally used in transis- 
tor sets, tend to induce rather a 
large amount of noise, which is 
undesirable in a pre-amplifier of 
any sort. 

A good quality a.f. transistor is 
also recommended; r.f. types, 
although more expensive are 
generally much noisier than a.f. 
types. 



Fig. I; Circuit diagram of the 
transistor audio prt-Qmpiifter. 



Input sockets 





COMPONENTS LIST 


VRI 


IMft variable, with on/off switch 


VR2 


5Qk.il variable 


VR3 


50k i 1 variable 


Rl 


5kQ±W 10% or 20% 


R2 


33kiHW 10% or 20% 


R3 


lOktHW 10% or 20% 


CI 


Q-Q005wF silver mica 


C2 


25jtF 25V electrolytic 


C3 


0-1 p,F paper 


C4 


25fiF 25V electrolytic 


Trl 


Milliard OC7I, or equivalent 


SI 


3 way, I or 3 pole. See text. 


Miscellaneous; 




6 input sockets with plugs, 2ft of co-axial 




cable, Ever Ready 1289 torch battery, etc, 



Construction 

The unit is constructed round the front panel, 
which can be made of either meial or wood, 
measuring 9in. x 3in. The four holes should be 
drilled in this panel, and the four controls mounted 
securely. Wiring-up may now be commenced, 
starting with the selector switch and finishing with 
the coaxial output lead. Most of the wiring is self 
supporting. A guide to component positioning and 
positions of holes is given in Fig. 2. 

All joints must be soldered, including those to 
the transistor. There is no danger of damage so 
long as the transistor leads are not shortened and 
the soldering process is carried out quickly. 

The tags of the three variable resistors may be 
used to hold the components soldered to them and 
the other components soldered to them will be 
supported by these. 



August, 1964 



PRACTICAL WIRELESS 



359 



LEARN - THE 
PRACTICAL 
WAY. 




your career . . . 
hobby . . . 

own business 

The demand for good Electronic Engineers is increasing 
almost daily throughout the world. Electronics is now 
the mott rapidly expanding of all industries with it* 
applications reaching into almost every sphere of human 
activity. If you are looking for a new career with new 
opportunities, then now it the time to choose— 
Electronics. If you are already employed in this field — 
then now is the moment to seek high qualifications 
to secure the top jobs which are waiting to be filled. 
Most of all, the great potential of electronic develop- 
ment meant unlimited scope for the future and wilt 
ensure a secure occupation for you — unlikely to be affec- 
ted by possible future recessions in other industries. 

The British National Radio School has had 25 years' 
experience of HOME STUDY coaching for students 
wishing to master the fascinating subjects of Elec- 
tronics — whether the object be career or as a hobby or 
new interest. The School is entirely independent and 
specialises ONLY in the teaching of electronic subjects. 
It employs only fully qualified staff to conduct and 
supervise each individual course taken by a student 
and it is this close and personal contact between Tutor 
and Student which we believe makes possible the sue 
cessful completion of a course of study. 

A special feature of our system is that all courses 
•tart right from the beginning and no previous know- 
ledge or experience is necessary or expected. Training 
is carried out in easy ctep-by-step stages using the most 
modern methods of tuition. The great advantage o 
the home study method is that it provides a complete 
self-contained course giving everything needed for the 
subject concerned and enabling work to be done in the 
comfort of one's own home and over any period of time 
desired. 

EXAMINATION COURSES 

• CITY & GUILDS TELECOM, TECHNICIANS' CERT. 

• CITY & GUILDS FULL TECHNOLOGICAL CERT. 

• A.M.Brit.l.R.E. EXAMINATION 

• RADIO AMATEURS' LICENCE EXAMINATION 

• P.M.G. CERTIFICATES FOR RADIO OPERATORS. 
t§ R.T.E.B. SERVICING CERTIFICATES. 



Laun — b r tmiliUm; — an 
iniMEaUooal reotlrar In 
tie toil QBiUty olua . . , 
aiue Hamilton , , . L,W. 
M.W. TWO SHOET 
WAVE Binds and VHF/ 
FM . , , ineoriwralst every 
modern receiver design 
teetinlane 





: 



OTHER COURSES 



MATHEMATICS 

TELEVISION 

TRANSISTORS 



• SERVO-MECHANISMS 

• COMPUTERS 

• RADAR & NAVIGATIONAL 
AIDS 



£0,093 obm/voli 
modern mult:- 
ranee teit meter 



Complete plet ur* way 
librarf ot theory books and 
I r attic* I manuals , . . 
NO MATHEMATICS! 

BUILD AND EXPERIMENT WITH ALL 
THE ABOVE— AS— YOU— LEARN . , . 

This is a new complete experimental course cuniiirising a 
mixture of theory and practical work using a ver> full 
range of electronic components and apparatus. Starting 
right from the beginning— or at a later stage If needed— the 
course enables the student to build tip all the basic elec- 
tronic circuits — amplifier; oscillator; recti Iter; detector; 
etc— and finally to the design, construction, testing and 
servicing of a latest design fully transistorised receiver 
using nine transislor> and covering long and medium wave 
and TWO SHOUT HAVEBAVDS plus VHF/FM reception. 
It is of real luxury ijualitv throughout — operates from a By. 
battery and can be used anywhere In the world, Every pre- 
sent-day technique In circuitry is covered and the course 
also includes multi-range test meter: signal generator and 
oscilloscope. By the end of the course the student will be 
able to deal with any type of servicing work with confi- 
dence and will also have a very useful workshop or equip- 
ment. Nearly 100 interesting and absorbing EXPERI- 
MENTS are carried out during this comprehensive course 
enabling anyone to gain full mastery of electronics. 




POSTINOW 



TO: BRITISH NATIONAL RADIO SCHOOL, RADIO. HOUSE, READING, BERKS, 

Please send me your free Brochure, giving details of your Courses, without any obligation, to:— 

NAME , "\ 

ADDRESS J 8 '?^ 1 

J am interested in. course above 

(We do not employ refiresen ta tivet) PW 8/64 



British National Radio School 



360 



PRACTICAL WIRELESS 



August, 1964 



%%ma£i/i^€&n\iA 



ELCOT LANE 

MARLBOROUGH * WILTS 

TELEPHONE: 657 and 658 







WIDE BAND 
UHF AERIALS 

forBBQnow 
and ITY 2 

FIVE STAR QUALITY AERIALS 

•fc Anodised elements for protection. -^ Modern 
plastic moulding techniques used for convected 
reflector and parasitic elements giving longer 
life. -^ Staggered spaced elements for maximum 
performance with all channel band width. 
•^ Multi-element reflector giving high back to 
front ratio. *fc Maximum efficiency of matching 
by using laboratory developed collector plate — 
without any other matching device. 



HotW 


Description 


Gain 
DD 


B/f 

Ratio 

OB 


Retail 
Price 


UF/H3 


3-ELEMENT, HEAD ONLY 
with CLAMP 


7 


(80 


31/6 


UF/H5 


5-ELEMENT, HEAD ONLY 
with CLAMP 


8-25 


19-5 


36/6 


UF/H7 


7-ELEMENT, HEAD ONLY, 
with CLAMP 


105 


24-5 


41/- 


UF/HIO 


ID-ELEMENT, HEAD ONLY 

with CLAMP 


12 5 


26 


47/- 


UF/HI2 


12-ELEMENT, HEAD ONLY 
with CLAMP 


135 


280 


51/- 


UF/HI4 


14-ELEMENT, HEAD ONLY 
with CLAMP 


150 


29 


55/- 


UF/HI8 


I8-ELEMENT, HEAD ONLY 
with CLAMP 


16-25 


30-0 


70/- 


UF/H22 


12-ELEMENT, HEAD ONLY 
with CLAMP 


17-0 


31-0 


85/- 



PLEASE STATE LARGE OR SMALL CLAMP REQUIRED 



DE-LUXE RECORD PLAYER KIT 



mi! an 1 Mullard 
and EZt*U), <mL, 

with 4 I" .lin. I'" 
j to li f.y ne production. 



-tout cabinet, charcoal i;n 
h matching blue rcllet. 
Size 1741m £ itiln. x Bin. 

Ca.1T. .v tnS. 10)- 
3QMPLETE KIT. Cat, * CoDSt. 
■[■-■LsliIs 2/8. ilrec with kit). 

f'KGNT SECTION, which house* 
ainp. & speaker is detachable 
iroin cabinet. Price, a* aetiarate 
unit for stereo, £5.17.6, i.'atr. j -. 



h. tJarrard Auto 
] «. aiupliller (BCLSfi 
and treble controls, 

1 1 tie yp*-aket, ^ujjctIi 
Dniemporacy styled 



COLLARO STUDIO TAPS RECORDER 
KIT, Regret all complete kits of this pop. 
liIat unit now sold out. Only a few cabinets 
ami Collars Tape Deck remain, NO AMPLI- 
FIERS LEFT, Cabinet size: 18 i 10} 
at Bin. with, cut-out mounting board. TAPE 
SPECIAL CLEARANCE OFFER— 
Twin track, 813,10,0. 4- Intuit, 
W7.10.0. Plus 10.'- carr. 




DECK BARGAINS! 



BARGAINS p LA YER UNITS 
.INGLE PLAYERS: Carr, 1 li . 
Model SRl-IO 5 sns, 
ttodel 4HF £19,10,0. Carr. 7'6 
AC TO CHANGERS: 4 speed. Carr. 
M-. Latest Model AT.6 -with 

transcription ami, plug-in head, 
mono. IB gns. Stereo 11 gut, 
•'Autoslim" Model £8,17.8. 



BSR MONARDECK. Tyoe TD2 

Twin-track £7.7.0 

Four-track: £9.10.0 

Carriage 5/- 

COLLARO STUDIO 3-SPEED 
DECK 

Twin-track £10.10.0 

Foiir-track £14.10.0 

Carriage 7;'fl 



EXPANDED ANODIZED METAL, 
Attractive jilt finish I In, x iln, 
diamond mesh 4/8 so.. It. Multiples 
of Bin. cut. Max. File 4ft. i Sfl., 
47/8, plus carr. 

TYGAN FRET (Coot cm. patt.), 
19 x 12in„ 2/-; IS i ISln,, 3/-; 
12 x 24in.. 4/-, etc. 



RECORDING TAPE 

Famous American Columbia CB? ■ 
Premier quality tape st NEW RE- 
DUCED PRICES. A genuine recoin- 
nded Quality Tape— TRY IT. 
Brand new, boxed and full\ 
guaranteed. Fitted with leadei 
i4nd stop foils. 

Standard Double Play 

(In. 600ft. 13/- 1.200(1. 3i;8i 
(fin, 900 it. 10/- LSfntfL. 37/ 
7lu. l/2O0Ft. 81/- 2,400ft, 47/8 
Post Hi Pack. 
Long Play per reel, If- 

5io. 900it. 17/6 plus 8d. ca 
Hio. LSSOOa. lfl/8 for additional 
7 in. l.SOrtft. 28/ 6 reels. 
SPECIAL OFFER, 3iu. Message 
ipe ISOIt. 3/9; 31n. L.P, tiMi, 
4,9; Sin. D.P. 30Q(t, B/e. P. i P 
per reel 6d. 

TAPE REELS. Mnirs. surplus 
7iu. S/3; irm, 2/-; sin. 9/-; 4ln. 
}/-: :tin. 1/3. Plastic spool coil 
lainera, Bin. 1/3; sin. 1/9; OJlii 
>/.;7in. 2/3. 



Tasok f.sl "t^Her UNITS 

Designer -a pproTetl kit* available. 
FMT1. 5 Ens. 4 valves 190/-. 
FMT2. £7. 5 valves 86/-. 
JTV Mercury, 10 gui. 3 valves 22/8. 
JTV3. £13.19.8. 4 valves 88/6. 
SEW JASON F.M. HANDBOOK 
2/8. 43 hr. Alignment Services, 
76, plus 2,'R. 



Condensers— Silver Mica. All values 
pF to l.uoO pF, 8d. each. Ditto 
Ceramics Bd. Tub. 4.10 v. T.t'.C. 
etc., 0.001 nifd. to 0,01 ami 0.1' 
330 v. 3d. 0.02-0.1/300 V, 1/-, 0.2o 
Hunt, 1/6. 0.3 T.CC. 1/B, etc., etc. 
Clow To], S/Micai — 10% 5pF- 

aoopp so. eoo-5,ouOpF i/-. i% 

2pF- 1 OOpF Bd. lOOpK-SOOpFlld. 
STSpF, a.OOOpF 1/6. Rtaiitorj— 
Full Range 10 uhiii«-10 meg. 
ohms 20% J and JW 3d., JW 5d. 

(Midget Me modern rating), 1W 
Bd,, '2W 9d. Hi-Stab. B% JW, iW 
Bd, [100 ohius-1 men.). Other 
values 9d. 1°„ JW. 1/6, etc, etc. 



TUB-ELECTROLYT1CS-CAN 

S6/35v. 50/lBv. 1/9: 8 + 8/4S0T, 4/8. 
50/SOv, 100/25*. 8/-; 32 +-38/876? ; 
4/6; 8/450Y. 4/3o0s. 213; S0/S0/350v. 
6/6; 16^18/450i. 5/6; 6O/2S0/275V. 
18/6; 3S-32/450V, 6/6; 100 -i- 200/ 
275v. 1S/B, 

Transistor Hidget types — all values 
1 mid to 50 mid, 1/9 «*., 100 mid, 
21- 12 v. 



EH AM ELL EB COFFER WIRE— } lb. 
reel* 14g-20g, 2/B; ■'•JR--J{ir. 3/-; 
:i(l.J-34a. 3/9: iOg-Ss^, 4/3; :w s -40c, 
4/6, «to, 

VALVE HOLDERS— Int. Oct.. 6d, 
Nylon or Ceramic , B70. £pa un- 
skirted, 9a. B7G, B9A skirled 1/- 
such; B7G with Can 1/B; B9A with 
Can, 1/B etc. 

STYLUS REPLACEMENTS. Diamond 
rttjii for L.P. or stereo, for all pop. 
type*. BSR, Collaro. Garrard, etc. 
11/3 ea. Ctd 12. raths. SAPPHIRE 
ditto. 5/3 ea. Conrp. range in stock. 



VOLUME CONTROLS— SK-'i Meg. 
ohms. 3in. 3P1NDLK3. MOB- 
Q ASITE im>9 BT T V !' I-:. 1 1 1 .1 . 
dla. Guar. 1 year. LOO or LIS, 
i-atios. leas Sw. 3/-, D,!\ Hw. 4/6. 
Twin Stereo leua Sw. 6/6. Some 
values with. D.F, Sw. 8/8. Specials 
to order. 



KNOBS — Modern Continental Types 
Brown or Ivory with OolJ Ring 
lin. dla. 9d. each, I ;in. 1/- each. 
Brown or Ivory with Gold ce&tre 
lin. dia., lOd. each: l]fB., 1/3 cat-h. 
l^iRtiE SKl.KCI UJS AVAII.ABI^ 



TRS 



BONDACOUST Speaker Cabinet Aeonstic Wadding (lin. thick approx.) 12in. 
J'.o'i'i^^b^ 1 ^;^ 1 ' 8 ft " 4I ' > J - TINNED COPPER WIRE. 16-22g. 
2 /B 41b. ERSIN MTTLTICORE SOLDER, 60/40, 4J, per yard. Carton? S/6 etc. 

We manufaeture all types Radio Main*" 
Tranaf.. Chokes, Quality Off Trane.. etc 

l^iiiuiries invited for Specials. l*rotolypee 
for small production rutis. Quotations by 
return. Send for detailed harguin lists, 
3d. stamp. 

Only a lew items are listed from our compre- 
hensive stock. Write now tor lull bargain 
lists. 3d. 

RADIO COMPONENT SPECIALISTS 

70 Brijstook Ra„ Thornton Heath, Surrey. Euuri: 8 a.m.-O p.m., 1 p.m. Wtd. 
THU21SS. Terms C.W.O. or V.O.JJ. Pott ana- patting up to j (ft, 9d.; I |J. 1/3; 
3 It. 2/3/ 5 to. 2/9/ S lb. 3/6. 




August, 1964 



PRACTICAL WIRELE... 
9 « 



361 




Coa x i a ( out put cable 



Fig. 2: Layout of components far the pre-amplifter, with dimensions for the four panel-control holes. 



The battery specified will have a very long life 
and therefore is a convenient source of power to 
use. If the pre-amp is to be used with a valve 
amplifier, the h.t, supply can provide power to run 
the unit. A suitable circuit is shown in Fig. 3. The 
10/iF 25V capacitor is for additional smoothing, 



Testing 

When all wiring is complete, the unit may be 
tested. Connect the output lead to a suitable 
amplifier, either valve or transistor, and feed in via 
one of the input sockets a suitable signal. The 
action of the Volume, Treble and Bass controls 
may be tested. 

Both Treble and Bass have a wide range of cut- 
off and this obviates the need for a middle " 
control. Indeed, with the controls set at minimum 
treble and minimum bass, the gain of the pre- 
amplifier is reduced to less than unity. 

In practice, of course, this state of affairs will 
never come about; the treble control may be set 
below maximum to reduce needle scratch on old 
78 r.p.m. recordings and the bass control similarly 
set to reduce motor rumble from a cheap turntable. 

As has already been mentioned, three inputs are 
provided. Various signal sources will load the pre- 
amp: a.m. tuner, f.m. tuner, gramophone pick-up, 
crystal or high resistance dynamic microphone, 
tape head (with a suitable bias oscillator) or even 
a simple crystal set will give very high quality 
results when coupled to a good amplifier. 

The P.W. Mini-Amp is very suitable. If the 
Mini- Amp is used, its volume control and the 
330ki2 resistor (Rl) should be disconnected and 
the pre-amp output fed directly to the base of Trl 
(V6/R2). 

It is a good idea to obtain a three-pole three-way 
switch, as the spare poles can be used to apply 
power to the various other pieces of equipment 
which feed the input when the respective input 
source is selected. This arrangement is shown in 
diagramatic form in Fig 4. 



Fig. J (right); Circuit 
of o/ternati've power 
supply unit, as dis- 
cussed in the text. 



Fig. 4 (below): Wiring 
for a 3-pole 3-woy 
switch to cater for 
a ,m . / f.m ./ gram 
switching. 



To VR1 



2Wl 






1Qui 
25V 



I 
1 



25QVH- 



•Tktl 

:2w 



x Input 
f sockets 




— > /^AA/v 

To power 
supply 



^cooooocc 

Power for 
AM. tuner 



The control panel may be given an attractive 
finish by cutting a sheet of cardboard to the exact 
size of the front panel and carefully writing the 
functions of the various controls on it and then 
slipping the card over the four spindles. A sheet 
of transparent plastic may also be placed over this 
for protection, if desired. 

All the spindles, should be sawn down to the 
same length of about £in., so that the knobs are 
almost flush with the panel. 

If a little care is taken in finishing, the appear* 
ance of the completed unit will match its excellent 
performance. 



362 



PRACTICAL WIRELESS 



August, 1964 



s m m m 



ACTON, BRENTFORD AND CHISWICK RADIO CLUB 
Hon. Sec: W. C. Dyer, G3GEH, IBS Gunnersbury Avenue, 
Acton, London, WA 

When the Club next meets on 21st July "Test Equipment for 
Transistors" will be the title of the talk given and all local en- 
thusiasts are invited to attend. 

BURSLEM AMATEUR RADIO SOCIETY 

Hon. Sec; J. R. Sherratt, G3SAJ, 23 Ash Way, Ash Bank, 

Bucknall, Stoke-on-Trent, Staffordshire. 

Members who attended the meeting lor 4ch June, took the 
opportunity of discussing the organisation of the Society and 
forthcoming programmes of lectures, prior to their move to new 
headquarters at Moorland Junior High School, Burslem, which is 
scheduled to take place during September. 

CHESTER AND DISTRICT AMATEUR RADIO SOCIETY 
Hon. Sec, : P. ). Holland, 19 Kingiley Road, Great Boughton, 
C heete r, Cheshire. 

On ?th June the Society met to discuss its participation in this 
year's N.F.D. Later in the month, on the 16th and 23rd respec- 
tively, members heard an R.S.G.B. recorded lecture and a talk by 
Mr. P, White on "Receiver Alignment". 

Activities for June ended on the 30th with a sale of surplus 
equipment, 

DERBY AND DISTRICT AMATEUR RADIO SOCIETY 
Hon. S*e.: F. C. Ward, G2CVV, S Uplands Avenue, Little- 
ovnr. Darby, 

.Aftw the N.F.D. activities of the weekend, members who 
attended the Wednesday meeting on I Oth June enjoyed a two-hour 
film show, This was followed on the 17th by the third d/f practice 
event. 

At the open evening of the 24th, junior members held a dis- 
cussion and on 26th June, G3ESB and G3IFA handled the local 
R.S.G.B. d'f qualifying event. 

July began with a surplus sale on the 1st. Then on 4th and 5th 
July, members of the Society took pare in the second I44Mc/j 
portable contest. 

DURHAM CITY AMATEUR RADIO SOCIETY 

Hon. Sec.: E. D. Watson, G3SHE, 5 Park House Road, 

Neville's Cross, Durham. 

This newly formed Society is proving very popular and any 
enthusiasts in the area who are interested in joining are invited to 
attend any of the meetings which are held on alternate Thursdays 
at the Bridge Hotel, North Road, Durham. Meetings start at 
7.30 p.m. Activities include lectures, sales and various contest and 
an R-A.E course is being run for beginners. 

On 18th June the Society's first Annual General Meeting was 
held. This was arranged so that members could elect a full corn- 
mint to replace the inaugural one which had held office (or an 
agreed six months. 

NORTHERN HEIGHTS AMATEUR RADIO SOCIETY 
Hon. Sec: A. Robinson, G3MDW, Candy Cabin, Ogden, 
Halifax, Yorkshire. 

Apart from manning an N.F.D. station on 6th June, this Society 
also provided a demonstration station at the Halifax Charity Gala, 
using the callsign G30MM/A. The same callsign was used at the 
Forest Cottage Gala in Halifax, where members of the Society sec 
up another demonstration station on the 27th. 

Activities for the rest of the month were all visits. The first of 
these, on 10th June, was to the Manchester Radio Society where 
several members met some old friends. A week later a party of 
members went on the first of three visits to the Moorside Edge 
transmitting station of the BBC. This was followed by an inspection 
of the Bradford factory of Wharfedale Speakers. 

Another visit had been arranged for the meeting of 1st July and 
this wai to the Bradford Fire Station. 



PLYMOUTH RADIO CLUB 

Hon. Sec: R. Hooper, G3SCW, 2 Chestnut Road, Peverell, 

Plymouth, Devon, 

In anticipation of numbers of mobile amateurs visiting the West 

Country during the sitOHMl months, members of this Club are 
attempting to contact as many as possible to extend an invitation 
co them to visit the City of Plymouth where they will find a wel- 
come at any of the Club meetings which are held on Tuesday 
evenings. 

READING AMATEUR RADIO CLUB 

Hon. Sec: R. G. Nash, G3EJA, "Peacehaven", 9 Holybrook 

Road, Reading, Berkshire. 

The June meeting was held on the 27th when the subject of the 
evening's lecture was "Receiver Alignment", The speaker was 
G, Preston, G30LA. 

ROYAL NAVAL AMATEUR RADIO SOCIETY 

At this year's Navy Days (lst-3rd August) the Royal Naval 
Amateur Radio Society will operate a special exhibition station 
from H.M. Dockyard, Portsmouth. The station will be located just 
inside the main gate and will be on the air as GB3RN on all amateur 
bands from 1 ,8Mc/s to l4SMc/s inclusive. 

Visitors to the Dockyard and the Fleet will be welcomed at the 
station. 

SOUTH SHIELDS AND DISTRICT AMATEUR RADIO 

CLUB 

Hon. Sec: D. I. Forster, G3KZZ, 41 Marlborough Street, 

South Shields, Co, Durham. 

On 21st June members enjoyed a mobile picnic held at Finehale 
Abbey, Co. Durham. 

SPEN VALLEY AMATEUR RADIO SOCIETY 

Hon. Sec: N. Pride, 100 Raikes Lane, Birstall, Leeds, 

The final meeting for the 1963/64 club-year was held on I Uh June. 
The following meeting on 25th June saw the election of the com- 
mittee of officers for 1964/65 at the Society's Annual General 
Meeting. 

WEST KENT AMATEUR RADIO SOCIETY 

Hon. Sec: H. F. Richards, 17 Reynolds Lane, Tunbridge 

Wells, Kent. 

After two years' absence, this Society returned to participation 
in National Field Day. On 12th June the annual construction com- 
petition was judged. Two awards — the John Wheeler Trophy and 
the VS9AW Trophy — were presented to the priie-winners of this 
competition. 

The last club event for June was on the 26ch when members 
heard an R.S.G.B. tape-recorded lecture on "Aerials". 

July began with an outside visit by a group of members to a local 
Decca Navigator transmitting station. 



COMPONENTS FOR THE "TRANSISTOR 
RADIO MAINS UNIT" 

Some readers have had trouble in obtaining cer- 
tain components for the "Transistor Radio Mains 
Unit" as featured in the June 1964 issue. The two 
diodes specified are now discontinued and replace- 
ment ones have been suggested by AEL They are : 
silicon junction rectifier type SJ103-F, costing 4s, 
post paid, and silicon voltage reference diode type 
VR9-F at 9s. 9d. post paid. 

All the components for this unit, including the 
replacement diodes are available from Electronic 
Constructors, Sutton Montis, Yeovil. Somerset. 
who will be pleased to submit a price list to any 
reader without delay. . 



August, 1964 



PRACTICAL WIRELESS 



363 



MORSE PRACTICE OSCILLATOR KIT 

A uuiflUtoTteetJ multi vibrator nwastirijig only 
21 x 1J x 4 Sin* Fundamental output beMBA. > 
1 T Q00 cJ'a. lialtery drain only 3 niA. Siu^N- 
Lus-truciLiOBiJ included. Complete with 
earpiece. Price 39/fi. P. <t P. 1/-. 



STABILISED POWER UNIT 

50 o/i uutnt input, Stabilised 130 v 
B.C. output and 0.3 A.C., optional 
J.:C. output from trinitiforiner tapping* 
at lfl(MM9u v. Primary tapping u 
at 30, 110 and malini voltage. Lncur- 
porfttea aeon fttabiJ-LsIn^ valves. 
Would be u**ful m battery eliminator 
for rJO t. equipment. Frwc Art /e 

With polished srtnrdy wooden cabinet and 




S2/6 



TRANSMITTER /RECEIVER NO. 46 

Compactly liullt to tie 
carried by one muL 
This has a range of 
app. 10 ml tea and being 
crystal controlled tun* 
ing is avoided and 
operation la at accur- 
ate as a telephone. 
Frequeney3.ii-9.lMcn. 
(Complete stations com- 
prising receiver trans- 
mitter, rod aerial, i 
iC '■ S of headphone, and 
microphones In canvas 
carrying bag, but less 
the plug-in cry ital/ 
coll units (these an 
easily obtainable). 
Brand new In maker's 
cartons. 

Price per rtatlon 

£4.10.0 f ,U 

Two rt&uoni tor 

89.10.0 ££ 




MORSE KEYS 

Mors* key assembly. 
Key with base, cover 
and terminals. Com- 
plete with le iid. 

£•*.*, 6/11 

2 Morse Keys for 12/8. Port ire 




H.R.O. HANDBOOK AND NOTES 
3 11 each 



NO. 19 SET INSTRUCTION 
HANDBOOK 3/1 1 EACH 



1155 INSTRUCTION HANDBOOK 
3/1 1 each p. •. 



VALVES 2/6 each 

P. * P. <W. 9 tor 6/- Post tree 

BBiG (new). ISA (new), DAM (new) ARF12 

(new), ATF-t. 



/ s^L* mm ♦ 

^►<^ 

NO. 19 SET TRANSMITTER RECEIVER 

Sew stocks Just arrived. Equipment comprises 

3 separate units built into one chassis and separate 

power pack. 

Specification: 'A" Sat Transmitter/Receiver 

Frequency coverage 2-4.6 nic/a and 4.5-8 mc/s. 

(150-37 metres). 

tor H.T., c.vv'.. or M.C.W. Range on H.T. lo 

miles. CW. 50 miles. Superhet R.X. I.F. 403 

fce/s, B.F.O. etc. 

li.X. valve line-up: 6K7, K.R: 6K8 miier. 

2 8K7 I.F.: 8B9 det. A.F. phone output. 

T.X.: 6 KB, mixer. B.F.O., EF60 buffer, EB34 

ABC, and output stage, which has to be -de- 

commissioned to conform with GPO requirements. 

Trensmitter/Recelver 2291241 mc/s. Local use 

up to 1 mile. Valve line-up CVS, 6K7 and BV8. 

Intercom set '2 valve A. F. amplifier for vehicle cil-w 

inter-communication. Valve hne-up &K7 and 6V6. 

A ti|in. meter is built In reading L.T. and H.T. 

voltages, drive etc. 

POWEK tritlT. 12 volt DC Input. Output 275 

volte 110 m,'a. aad 600 volts SO m/a. Equipment 

Is of American or Canadian manufacture and Is 

supplied in good condition. CA 4 A A 

PBiCE complete with Power Back ***■ ' VmV 

Carriage 17/8. 

18 set only fl 1 A fi 

Carriage 10/- ■"*• I VmV 

Power Unit only jiM 

Carnage 101- * ■ 

Two IB sets complete with CO I A A 

Power Packs. »*>• I U.U 

Carriage 30c 
If MMtl 

Handbook 8/6 P. A P. ed. 

Connectors 15 pin , , . . 18/8 P. A P. 2,'fi 

6 pin . . . . 7/8 P. 4 P. 9)6 

Control Boxes, Single, new . . !/8 F. < P. 3/1 

Whip Aerial* Sit, Bin 7/8 P. 4 P. '2:8 

5it 4/8 P. 4 P. a/a 

Headphones and Mlfca , . 17/6 P. 4 P. 2/8 

Headphones less mike Insert , , 5/- P. 4 P. 

TRANSISTOR SALE 

Mullard OC44 (P. 4 P. 3d.) 8/U 

Mullard OC4B (P. & P. 3d.) ., 3/11 

Milliard OC71 (P. 4 P. 3d.) 2/11 

Mullard OASOtP, t P.M.) 1/11 

Edb*wan XU202 Germanium diodes 

(P. * P. 3d.) 1/H 

Mallard OA7»(P. 4 P. 3d.) 1/11 

Translator holder 3 -pin (P. 4 P. 6d.) 1.0. each 

MICRO ALLOY TRANSISTORS 

Mat 100 7/9 

Mat 101 8/8 

Mat 120 ,, , 7/9 

Mat 131 . 8/8 

VHF Transistor ADT140 151- 

Above MATS postage paid. 

Ferrite Slab Aerials suitable for transistor 

sets , 8/-. P. 4 P. fld 



IMPEDANCE MATCHING UNIT 

An imped uiiee roMcning device enabling both 
high and low resistance phone* to be used trom 
may given pice* of eijulpuient. In- 
urporatea a m "-*^hinB Uuufonner 
-uvrloaied in a metaJ ca«e with pa T ^ HTt 
terminal board. Foot staudaxd laci 
irockets enabling four pain of phones 
to be need aicuuitAaeoiirjir —two HK 
mid two LB. 



&. F. SKA, 



19/11 



POWER UNIT 4 LF AMPLIFIER 

For the 88 act. In good condition employing 
modern valves and built-in vibrator pack. 
Excellent smoothing facilities. lEv. operation. 
Many applications. Including QQ ||!P. 4 J 
use with car radios. '•/» 5/-. 



BM3/S0NA STREAMLINE 
MICROPHONE STANDS 

TYPE 1 

Heavy metal base. Black gloss fmiah, 
i^~H^V6. P. 4 P. 2/8, 
TYPE 2 

rhroiue unlab. Telescopic desk stand extending 
to 1:1m. height, heavy black glow base. 26/-, 
P. 4 P. 3K 
TYPE 3 

Floor stand, 3 sections. Chrome hniah. Heavy 
base, 86/-. P. 4 P. 3/-, 



SPECIAL OFFER 

High Impedance lightweight headphone* ideal 
for crystal sets. Only 11/- per pair, or two 
jmlrs for £1, P. 4 P. 1/a each. 

DYNAMOTOR 

Run all your mains AC/DC equipment from 
your car battery, Gv. input gives 2oUv. output, 
or l'iv. Input gives SOOv. output at 30 watts. 
Very low battery drain. Slie only Sfia. x 34in, 
A most for the cai»vs>nner. ne } 

Only **»l~t, * T. 3/6 

LEAD ACID 

ACCUMULATORS 
(Untplllable) 

2 volts at 18 A.H. Brand 
New. Size 4 x 7 X Sin. 
4/11 each. 

3 (or 12/6. 
per MIL 




UNIVERSAL PLUG 

Plug into all so ckets with the 
NEW TTSJIYERBAl, PLUG. 
Saves money. Saves time. Fits 
all 13, 15 4 6 amp. 2 pin. 3 pin 
sockets and adaptors. Easily 
adjustable. Robust construc- 
tion. Only 12/6. P. 4 P. lid. 




9v. BATTERY CHARGER AND A.C. 
ELIMINATOR MODEL LA. 6P. 

"must" for every transistor set owner! 
Save those batteries by running your transistor 
set direct from AC mains this summer. Reacti- 
vate all youT old PP3 batteries. Unit contains 
neon indicator and standard battery connect 
tlona with nearly 2 yards of mains leads and 
plug. Also snap cord fur cuoiu<ctipn to get. 
NOW ONLY 4fl/g I l p. -m 

4 CHANNEL TRANSISTORISED 
SOUND MIXER 

Add musical highlights plug additional sound 
effects to your tape-recorder. This LustruroeAt 
permits mi. ting of 4 signals such as microphone, 
record player, radio tuner, etc., Into single 
output. Fully transistorised and self contained 
In handsome cabinet. Price 5S/tl. Post free, 
.standard lack plugs to fit same, 2/6 each. 
P. 4 P. fkL 2 for 4/8. P. 4 P. Bd. Chrome 
shielded 3/8 each. P. 4 P. Bd. 2 lor 6/8. Post 
irtc. 

♦♦ ♦ ♦ v 1 t £ "$"$ > 4"3"$ j $»4'4- v- ♦ ♦ t $ 1 
RESISTORS 

Special offer. High quality J watt resistors. AS 
preferred values (state values required). 
Hi ii-io meg. ohm. 3 id. each, 6 tor 1/8, 12 tor 
1/S, 100 for 24/-. 



NfcVV V\ AI,K BOWD STORE OPE> IN LAMBERTS Alt CADE, LOWER. BHIGGATE, LEEDS 1. NEXT TO HALFORDS 
CYCLE SHOP. OPE.\ ALL 13A1 SATtIKI>.\Y. 48 HOUR DESPATCH SERVICE. *"»^* 

ALL MAIL ORDERS TO OL'R HHII.G VTK HOlSf ADDRESS. 

TRADS ■liVPl B rjtT> 
CASH WITH ORDER, I ^tjK ^^kW99^^^^^U ***»«• wrnaau 

a^hkw '^B^B^BSV^ J^^. ^^9M. ^ WW ^H nnrig Pl WHOM 

6/- SXTBA OH C.OJ>, ■ 

ORDBBS 

Ho aO.D. onder 80/., 

JONA ELECTRON I CO. (Dept. PW8) ( Bl .GATE USE, 1 3 ALBION PL, LEEDS 




364 



PRACTICAL WIRELESS 



August, 1964 




Wide-range Transistorised 
SIGNAL GENERATOR— Model 27 

Range 150 Kc/s to 350 Mc/s. 
«fr Accuracy better tban 2 % 
■fc Directly calibrated 
Skr Battery operated 
ie Compact and light 

£9.12.1 

with test lead and battery. 

Post and Packing 3/6 extra. 

1LP. 48/- deposit and 27/- monthly. 

Trade and Export Enquiries Invited 



NOMBREX 



INSTRUMENTATION 



Wide range Transistorised 

INDUCTANCE BRIDGE 

Model 66 

■* Range lai to 100 H 

-*■ Inductance to 5 % accuracy 

■yt Measures Q and Tan § 

-k Balance by Miniature Meter 

ic Compact, only 6J x 4J ins. 

ic Portable, weighs only 2 lb. 

dflft A €% Battery 2/3 
EIO.W.W p_ J, Pkg 3/6 

H.P. £5 deposit and 49/- monthly. 





Wide-range Transistorised 
C.R. BRIDGE— Model 62 

6 Ranges: m to 100M 
lpFto lOOpF 
■A" Visual null indicator 
■fc Power factor check 
•fa Electrolytic leakage test 
■dr Batterv operated 

£8.7.3 

including battery. 
Post and Packing 3/6 extra. 
H.P. 40/- deposit and 24/- monthly. 

S.A.E. for full technical leaflets 



NOMBREX LTD. 



Instruments ESTUARY HOUSE, CAMPERDOWN TERRACE 
Division EXMOUTH, DEVON. Phone: 3515 



THE 

PEMBRIDGE 

COLLEGE 

OF ELECTRONICS 

PROVIDES TRAINING 

IN RADIO 

AND TELEVISION 



FULL-TIME COLLEGE COURSE 
IN RADIO AND TELEVISION 

Our Course has now been extended to sixteen months' 
duration to include theoretical and practical instruction 
on transistor television receivers, U.H.F. television re- 
ceivers and colour television. 
Next course commences 2nd September, 1964. 
This Course is recognised by the Radio Trades 
Examination Board (R.T.E.B.) for the Radio and 
Television Servicing Certificate examinations. 
Provides excellent practical experience on valve 
and transistor radio receivers and all well-known 
makes of television receivers. 



To; 

The Pembridge College of Electronics (Dept. Pit) 

34a Hertford Road, London, W.2. 

Please send, without obligation, details of the 
Full-time Course in Radio and Television. 



Name- 



Address. 



August, 1964 



PRACTICAL WIRELESS 



365 



A 4-VALVE, 

4-BAND, 

ALL-DRY 

SUPERHET 

PORTABLE 



By L. R. Repage 




The 
CHEL 



ER 4 



CONTINUED FROM PAGE 247 OP THE JULY I5SUE 



THIS month we continue with the main 
assembly. Owing to the closeness of the com- 
ponents, particularly between coil-unit and the 
gang capacitor, it will be impossible to make 
the few final connections necessary unless the 
following procedure is strictly adhered to. 

Presuming that the below chassis wiring has been 
completed, this including the l.f, section in its 
screened compartment, the above components can 
be assembled. However, firstly connect two short 
lengths of bare flex to osc, grid and control grid 
tags respectively. These should be about £in. long, 
and should be twisted around and nipped tight 
with pliers, then soldered to the tags. 



FITTING THE COIL UNIT 

The coil unit can then be fitted in the elongated 
hole, but the nut not fully tightened. The osc. grid 
and control grid leads below should then be 
soldered to these short leads just mentioned, as 
close to their tags as possible. Take care to 
identify these leads correctly — it is so easy to get 
reversed connections and then, of course, the coils 
do not function correctly. The third loose lead osc. 



anode should then be soldered to the appropriate 
tag. Finally, the h.t. tag must go to the h.t. line, 
and if R2 resistance has been included with its 
miniature decoupling condenser C3 on the unit, 
a direct connection only is necessary. 

Next fit the ganged capacitor by its three set 
screws, and solder on the two short wires from the 
coil unit to the aerial section and oscillator section 
respectively. The short wires may have to be bent 

slightly to rest exactly on the tuning capacitor tags 
before soldering. The other tags on the tuning 
capacitor can conveniently be utilised for making 
the parallel connections to the vernier gang; but 
these connections will have to be made first, by 
short, but thickish flex leads near the l.f. screen. 
These leads should not rest on the screen of course, 
or the vernier effect of the capacitor will be 
shorted. 

This twin vernier may vary in dimensions so 
take care that sufficient clearance is given between 
the twin vernier and the main gang moving vanes. 
This point should be checked before drilling the 
holes for this vernier in the chassis, of course. 

The padder capacitor bank can next be fitted by 
soldering its " earthed" side to the E main wire, 
and the four trrnmer free tags soldered to the 
adjacent tag board of the coil unit by short lengths 



366 



PRACTICAL WIRELESS 



August, 1964 



Insulated 5leeving 



H.T+ bus-bar 




of flex. (Construction of the 
padder capacitor bank is des- 
cribed below.) 



Centre spigot 
of each valve — 
holder to be earthed] 

iTo Oryfoff switch 
_ HI- section 



Soidered to 
coil unit 



Fig. Sat An underside view of the chassis showing the wiring in part. 




ToVRl 
(top end) 



Fig. Sbi The component layout of the a.v.c. pane!. 



THE A.V.C. PANEL 

Finally the a.v.c. panel can be 
similarly fitted by soldering the 
'* earthed " connecting tag to 
" E " main wire. The leads to this 
panel will, of course, have to be 
brought out from the chassis 
wiring, and it is a good plan to 
stick a paper label on each so 
that the correct tag is used. 
Colour-spots on tags and leads 
might be a useful procedure 
here. 

The a.v.c. panel is shown in 
Fig. 5b. Again this was an experi- 
mental arrangement and allowed 
for easy change of valves of com- 
ponents. Four connections are 
taken from it to various points in 
the set, but more will be said of 
this later. The miniature button- 
type potentiometer VR1 and the 
two pole on /off switches S3 are on stand-off panel 
No. 2 and wires from the inside of the set are 
passed through holes to them. The button potenti- 
ometer stands off the panel by suitable set screws 
and washers and has a clearance hole cut in the 
outer cabinet. Another pattern could, of course, be 
used with the more normal spindle, but may 
necessitate altering the on /off switch. 

The fuse is a flashlamp-type bulb of 1-5V, -0A 
rating and is a worthwhile fitment. 



PADDER CAPACITOR BANK 

The padder capacitor "bank" is made up by 
soldering the four trimmer capacitors to the brass 
strip by one of their tags, each component being 
pushed close up against its neighbour. 

The tags at the opposite ends go to the small 
panel on the coil unit. 




Bl,Ct 



To audio „ _ | 

transformer Heater 

tsec.) — ve 



SOW" 

-velvi 1+v. 

Heaters 

'*"™ w (S2a) 

Fig. Set Connections to the valve bases. Valvehotders shown as seen from underside. 




August, 1964 



PRACTICAL WIRELESS 



367 



>*o*^*o»o*Q ^ *a * m r a»% t a ^o »\*c a ^o ^ qj » ^o »fc <= > »*■ *= >-^-«&-^«; 



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• Instruction leaflet supplied. 

• Crystal pjck-up with expendable 
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• Operates trom aSV battery (3/9 ezt) 

• Available Id two colours — cream/ 
red or cream/blue. 



• A real "FAMILY FAVOURITE". 

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• Assemble one of these amazing 
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supplied In 3 complete units with 
only 10 connections to make 
Approximate dimensions 9x8tx41n. 



^ Motor and pick-up deck (2/6 P. & P.) 'IQ/fi ONLY 

O Ready-built 4-transistor amplifier, complete «E l 

mm with volume control and L'speaker (2/- F, & P.) "*»/■ 

Q Portable two-tone case with handle, and C I 

w expanded metal fret (2/- P & p ) **f " 



796 

the complete Pckgs. 
<plus 5/- P. 4: p.) 
or any unit sold 
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ALLOW 2/- each Speaker lor poet^e ui I packing, and please siwaify the exact requirement* — the nearest available will be cent. 



intihmt Priem\ 

6 8/8 

I 10/- 

4 10/- I 1 

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Constructional data 1/9 Post free. 




(The best and 
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M L LLARD 

Transistors 

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ail components 

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. Inclusive iirice tor all associated component*, ease, battery 
and Instruction Book complete in every detail. 
• AMY PAKT8 BOLD SEPARATELY ON THE 

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CAPRI $£& 79/6 g 1 



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(Beautifully greared AM/FM 2"ganj* Condensers, 4/6: .AM/FM IFT's 465 kc/3 and 10.7 Mc/s, 4/8 pair: Msgnavox Crystal Tape Recorder < 

, Mlkos, 12/6:ftrans;stor sub min. 7 mm. coil set (4) 4/6 the set; 3 watt Stereo Amplifiers, complete, ready to switch on. 79/6: Senteroell I 
rectifier.-; R3/2D-D3-2-1-Y. 2/6 eaoh. DIODES— OA70, OA79, OA90, CCI46H. GD10. 21- each. wwii 

TRANSISTORS: OC43 4/6, PXA101 S/0, AP115 4/6. Sub mln. Germanium diode 1/3, Ml diode 6<L eaoh. Silicon diodes. 200 p.i.v.. 200 mA ] 

1 V- each. 400 P. I. v., 330 mA. 2/6 each. ] 

Please send STAMPED and ADDRESSED envelope with any enquiry. We regret no catalogues — our stocks move too quickly' Kindly 

) make_pro visl on for additional postage and packing charges to avoid delay. Terms: Cash With Order or CO J}, on Order* over 16/-, 



368 



PRACTICAL WIRELESS 



August/ 1964 



ARE YOU TRAINED FOR 
1965 1 1966 X I967t 

VOTJ AKE GOING TO BE THE MAH IN DEMAND1 
Fever before In history oas it beeti so easy and bo inexpensive to train lor a 
rtwanllug career in Electronics, lindio and TelO'lsion! 

BIM-TEOI1 \OW OFFER TltllEE EXCLUSIVE HOME TBAINIKa 

COUKBES. 

Anyone can afford these amazing courses — auyone can understand tnit practical 

training— No complicated mathematics to hold you uack— So old fashioned, 

OtttCUre explanations '■■'■ :: ! L>':-ar./ y.-:n! 

Huslesros «e CEYSTAL CLEAE. PRACTICAL. EASY TO MASTER AHD 
USE— Early lessons make lundami-ntalit clear oven to the beginner, while other 
lessons will give von the practical "know-how" of an expert! 
Compares favourably with some courses co«l lug very mucb more! By eM»ttnf 
a mass market through large toIuiub sales and eliminating Individual letter 
writing we are able to pass on these savings directly to yon] 
Each course is printed, on extra large quarto aiia sheets and bound Into on* 
manual to simplify handling and distribution. 

Pleaae select the comae moat suitable for your requirements from the following, 
HO. I, RADIO COURSE. Fund amenta I facts— Electrons — Conductors and 
Insulators— Radio Batteries— Circuits— Masaetlsm— Ohm's Law— Kesbtur 
Colour Code— Chart— What resistor to nn«— Electro- Magnetism— Electro- 
magnetic induction— Bell Induction— Radio Frequency Inductances— Cauadl y 
Coupling— Elf. Transformers— Radio Culls — Hadio Capacitors— The haraii— 
Dielectric — Capacitor Colour Code — Alternating Current Theory * Filte re- 
Reactance and Resistance — Charts to calculate Capacity Frequency and 
Inductance— Handy Radio Formulae— Practical Aspects of Radio Servicing — 
Radio Valves — Transistor Theory — H Type Ocnnaniam— P Type Germanium — 
Diode Action— Transistor Action— D.C. Stabilization— Transistor Bias Aiitu-t- 
■nent — R.F. Amplification — Snperheierodyno Principles — A.V.C. — Power Sup- 
plies— Meters — MnltiiesterB and Valve Testers — Point to Point Servicing — 
Signal Generators and Sisfoal Tracers— Using an Oscilloscope for Servicing— 
Alignment— Amplifiers and P.A. Equipment -Hisli Fidelity— Advantages of 
Inverse Feedback— Speakers— Frequcm-y Modulation— How to Obtain Sadie 
Job*. Price for the complete course . ONt,Y3B/-. Plus postage 1 S. 
Vo. B ELECTRONICS COURSE, Includes most of the aliove lessons plus L.O. 
and B Combined Circuits — Resonance Phenomenon— Behaviour at. Resonance — 
How Meters Work— Making » Voltmeter— Ohm meter Connections— Valves— 
Electron Behaviour— Triode— Characteristic Curves— Power Sop piles— Audio 
Amplifiers — Microphones— Resistance Coupling— Obtaining Grid Bias — 
Pub. Pull and Parallel — Phase Inverter Circuit — Radio Frequency Voltage 
Amplifiers— LP. and Mnltlband Colls— Detection— Receiver Circuits— He*ult» 
of STeqnencv Mixing— A. V.C, — Electronic Oscillators — Qnarti Crystal*— 
Itadio Transmitter Circuits— Modulation and Tuning— Lines, Antennae and 
Radiation — Test Equipment Using Meters — Electronic Test Equipment — 
Tnyratrooa — Photo-CeE Equipment — Radio Compass — ET. Heating — 
Electronic Shaping Circuits — Electron Microscope— Electric Strain Cauges — 
Inter-Communicators— Radio Servicing Techniques— Servicing Printed CircaiU. 
Priee lor the complete coarse. Only 39/8. Flos pottage 1/6. 
Graduates ol the Eleotionini Course can qualify tot a eartmeate— detain mat 
with each order. 

Bo. S. TELEVISION COURSE. Effect of Mis-adjusted controls— Pictures of 
Tarfooa faults — Service adjustments — Circuit Faults Indicated by a Poor 
Fetters— Finding Bad Valves by observing Picture Faults— Separate Channel 
IF. By stem — lutercarrier l.F. System — Negative Picture — Interference— 
Antenna Principles and Practices — U.H.F. Transmission Lines — Facts About 
the T.V, Signal to Help von In Service Wort — Synchronizing Separators— T.V, 
Interference Aids— All about Cathode Ray Tubes— Explanation of T.V. Circuit* 

Video Detector — Video Amplifier — D.C. Restorer Circuit— Automatic Gain 

Control Circuits— Oscillators—Deflection Coils— Automatic Frequency Control 
Ctoonita — Analysis of Stagger Tuned l.F, Receiver— Analysis of Three Inter- 
Canter Type Receivers — The Vertical Deflection Circuit — The Horizontal 
Deflection Circuit— "Waveforms — Schematics of various sections of » T - J ■— 
XJ.H.F. Converters and Tuners — T.V. Test Equipment and Alignment — Analysis 
of Various Problems. 

Prioe tor the complete course. Only 38/-. Plos pottage 1/6. 
UNCONDITIONALLY GUARANTEED TO GIVE COMPLETE SATISFACTTOII 
You must be convinced that this is the best valne you have ever seen In Elec- 
tronic. Radio or T.V. Training, otherwise you ean return the course (or have 
your money refunded tf sent with order) after you have examined it In your 
own home for a full seven days. 

IF TOTJ SEND CASH WITH ORDER WE WILL INCLUDE A FREE 70 PAGE 
BOOK Tick on the coupon one hook for each course oriie red w ith full cash. 
RADIO SERVICING FAULT FINDING BOOK. TELEVTSIOH FAULT 
BOOK. OSCILLOSCOPE BOOK. „ , . 

These free books are authoritative, and loaded with information. Would 
cost at least 6/- each if bought separately — by sending cash you reduce book- 
keeping and other costs, which savings we paas back to youi 
*•» eaai sent — — ■ p R E E TRIAL F FE R l • ■" ~ — — »m» 
Fay only 61- per week If yon wish. Clip coupon right now for this special offer. 
To: Sim-Teen Book Company. DepU CW3. Gator's Mill, West End, Sonthampton, 



•end the following course* for a full **ven day's trial 
] UL RADIO COURSE. □ Bo. 8. ELECTRONICS COURSE. 

S7/6, mol. portage, *1K inel. postage. 

□ BO. 1 TELEVISION COUBSaV 

37/6. inel. postage. 
CTree trial customers tick only one please). 
H lttt delighted, I may return the course post-paid without further obligation 
ea my part. Otherwise I will pay cash pries OR S/- weekly until purchase 
pitoa phis 2/6 service charge has been paid. 
J Tick here If enclosing full purchase price. 

Pleaae send me VJ FREE. RADIO FAULT FINDDJQ BOOK. 

□ FREE. T.V. FAULT PINDLNO BOOK. Q FREE. OSCILLOSCOPE BOOK 
Amount enclosed f 

t maderetand that you will refund this money in full tf I am not 100% aaUaoad. 
Ovaneu customers please send fall amount (fnrlnriing Ireland). 



Ooontr. 



£11 



ELIMINATE MAINS 
FLUCTUATIONS 

WITH THE I LU 

Automatic Mains Stabilizer 

providing constant perfectly 

stabilized voltage supply. 

MOVING PARTS 

ATTENTION 

MAINTENANCE 

Suitable for both 1 10 and 

240 V AC. Accu racy : ± I % 

Capacity: 250 VA 

IMMEDIATE RESPONSE 
In attractive vented metal 
case with leather handle. 
-•_ Size 8* x B", weight 21 lbs. 

,1 DS Carriage/Packing 12/6. From stock 




NO 



CHy- 



WORLD FAMOUS SLID-UP' VARIABLE 

TRANSFORMERS 

•kRATED CUR- 
RENT CONSfS- 
TENT AT ALL 
PO/NTSALONG 
THE WINDING 
Output: 0-260 v. 
Input: 230v. A.C. 
50/60- 

Shrouded fully 
variable trans- 
formers for 
bench or panel 
mounting. 

Model SB5 
5 amp. 




2.5 Amp. £5.17.6 
5 Amp. £9.0.0 



I J Amp. £18.5.0 
20 Amp. £32.10.0 



Ex Works 



MODEL AT- 1 

ONLY 

£9.17.6 



P. & P. 5'6 



TRANSISTOR TESTER 

FULLY PORTABLE 
PRECISION INSTRUMENT. 
MEASURES: 

Ico (Icbo) and the reverie 
current of diodes. 
PNP & NPN — 0-SOu.A 
(litA per scale), 
POWER— 0- lmA(20jtA 
per scale). 
35-200 (5 per scale) 
Bias current — 
(ImAon PNP& NPN) 
(5mA on POWER) 
aO.9-Q.995 (from £= av 
\-a) 

Terminals! Spring Sockets and 

Screw Terminals. 

Meter.' 4in. 50jjA moving coil. 

Size and Weight: 7xSx 3in. 2| lb. 

Powered by pen cells. 




TELESCOPIC AERIAL MASTS 

20FT. TELESCOPIC MAST. NEW. self-supporting all steel 
tubular 4-section masts, suitable for roof or wall fixing, as well 
as base location. May be extended to full height or locketi atany 
position by special Roller cam locking rings. Bottom section 
approximately I i*n. diam. Copperised and ONLY £5.0.0 
sprayed finish. Weight 16 lb. Carr. 7'6. 

LIMITED QUANTITY 
36ft. BRASS TELESCOPIC MAST 
Complete with built-in hand winding winch for easy rapid ex- 
tension. Finest quality non-rusting. Bottom section 2jr* diam. 
Winds down to 9ft. One of the best masts ONLY £35.0.0 
ever produced. . Carr. 30'- 

As supplied by us to shore stations and electronic organisations. 

I.M.O. LTD. 

Dept. P.W.4. 2-5 Pew is Mews, Westbourne Park Road 
London W.I I. BAYswoter 1756. 



August, 1964 



PRACTICAL WIRELESS 



369 



To give added support to the "bank" a stout 
tinned wire should be soldered to the outside of 
the shank of the adjusting set screw of each 
at the back, taking care not to allow the solder to 
run into the threaded portion of the shanks. This 
stout wire and the brass strip, are soldered to the 
lower chassis bar and give adequate support for 
this unit. 

The author fitted all 500pF padders though 




ALTERNATIVE VALVE TYPES 

There are several " alternatives " for the valves 
which have been specified. See Table 1. 

The centre spigot on each valve should be 
earthed, since this makes connection with the 
screening can. 

Noic that V4 has pins 1 and 7 joined to 1.L+. 
This is essential for T5V working, in this type of 
output valve. However some valves can be obtained 
with the normal filament connec- 
tions for 1-5V operation, as per 
VI. V2 and V3, their filament 
connections being to pins 1 and 
7 as shown. 

BATTERIES 

The batteries used with this 
set are the Ever-Ready A.D.35, 
1{V for filament, and the 



Looking into the back of the com- 
pleted receiver 



other values can be substituted according to the 
coil makers' instructions. 

A maximum value of 150pF is given by Messrs. 
Osmor for their Q09 long waveband oscillator 
coil, though the author has not found the 500pF 
one fitted gives too coarse an adjustment. 

Once adjusted for correct alignment, these 
oscillator padders are left alone, of course, as are 
also the slug trimmers in the oscillator coils them- 
selves. 



compact 90V battery B.126 for 
hi. 

The author has not tested the 
length of life of this h.t. battery 
for continuous use, and prefers 
to use it only when taking out as 
a portable. For indoor operation 
the author uses an Ever- Ready 
8.107. This larger battery cannot 
be accommodated actually in the 
set of course. 
The h.t. current consumption 
was found to be 1 2mA. 







Table 1 








Mullard 


Osram 


American 


Mazda 


VI .. 


DK92 


XI7 


IRS 


ICI 


V2 ., 


DF9I 


WI7 


IT4 


IF3 


V3 .. 


DAF9I 


ZD17 


IS5 


IFD9 


V4 .. 


DL94 


NI7 


3S4 


IPIO 



Next month details of the frame aerial and 

cabinet will be given. 



TRANSISTOR TUNER/CONVERTER 

— continued from page 323 
following table gives spot frequencies:— 



L.F. H.F. 

Tracking Tracking 
point . point 



H.F. 

Band 
end 



L.F. 
Band 
end 
Range 3 — 

l-67Me/s l'83Mc/s 4-SMc/s 5-3Mc/s 
Range 4 — 

5-0Mc/s 5-5Mc/s J3-5Mc/s 15-0Mc/s 
Range 5— 
-10-SMc/s ll-5Mc/s 28-5Mc/s 3I-5Mc/s 



The h.f. tracking point should be approx. 15" 
from minimum and the l.f. point 20 s from 
maximum, Note what has been said about the 
J 9m band earlier and if it is desired to include this 
on Range 4, trim the h.f. end accordingly to 



minimum, about 16Mc/s. 

Oscillator Pulling. When adjusting the sisnal 
circuits, some slight detuning of the oscillator can 
occur (pulling) and in order to prevent this effect 
giving a false peak, the tuning capacitor should 
be slightly rocked to and fro while aligning either 
mixer coil or trimmer. 

Second channel. Owing to the fact that an r.f. 
stage is used, second channel images will not be 
obvious. It is, however, essential that one uses 
the higher frequency of the two always present 
in a mixer, so if two settings arc found during 
adjustment of trimmer or core of oscillator coils, 
the one with the trimmer or core furthest out is the 
right one, thus putting the oscillator above the 
incoming signal. 

Check on this by moving the core bcnh wavs 
on lower frequencies, and if two similar signals 
appear, the correct one is the furthest out ""The 
same app.ies to trimmer TC7 on the hieh 
frequency end of each range. 



370 



PRACTICAL WIRELESS 



August, 1964 



A SSSS, MICROPHONE 



THE unit tu be described was made for home 
entertainment purposes, and has given much 
pleasure, although it is certainly not in the 
hi-fi class. 

The carbon was obtained by crushing the rods 
from old dry batteries, and is sandwiched between 
two Meccano plates, each 2|in. square, although 
they can easily be made up from sheet metal. Also 
required are two pieces of plywood, each 2|in. 
square, and some iin. x ^in. balsa strip. In the 
prototype, 3-ply only ^in. thick was used, so that 

woodscrews 
plywood 
1*bott 

Meccano plate 

»wer s!de\ 
scraped / 




and they must fill the space completely, or the 
microphone will make rattling noises as it is 
moved. 

The two large paper washers and the upper 
plate are laid on top. This plate acts as the 
diaphragm; its lower surface and one upper corner 
is scraped clean. (This corner must be over the 
enlarged hole in the lower plate.) 

The upper piece of plywood is used to cover the 
diaphragm, and present a neat appearance. A Hin. 
diameter hole is cut in its centre with a fretsaw (or 
a pattern of holes may be drilled), together with 
small holes in the corners for screws. Through one 
of these, a bolt lin. long is passed, and a nut 
screwed up tight. 

A hole is drilled through the scraped diaphragm 
corner to the back. Washers are placed on the 
screws in the other corners to the same thickness 
as the nut, and the diaphragm cover is screwed 
down. The boh from the top plate must not touch 
the lower plate, A further nut and terminal are 
placed on this bolt. 

The corners can now be rounded off, and tl 
microphone painted, if so desired. 



■Thin plywood 



ftg.l t Illustrating the simple construction of the 
microphone. 

the finished microphone was both light and slim. 
The balsa wood can be obtained from any do-it- 
yourself shop. 



Construction 

Construction is shown in Fig. 1. The lower plate, 
with its upper surface scraped clean of paint, and 
one corner hole enlarged, is glued over one piece 
of plywood. (Evo-stik is a suitable adhesive agent.) 
A hole is drilled in the centre of the plate to take 
a small bolt, and a nut and a terminal are fitted to 
the bolt. The balsa sides are then glued in place. 

The tray can now be tilled with the crushed 
carbon. The panicles must be as small as possible, 



The Circuit 

The circuit is shown 
phragm vibrates, the 
terminals varies. When 



in Fig. 2. When the dia- 
reststance between 
a voltage is applied, tl 




Fig .2 1 The input circuit used with the microphone. 



varying current induces a varying e.m.f. on the 
secondary of the transformer, which is amplified 
in the usual way. 

A microphone transformer with a ratio of 50 : 1 
will be suitable. The author used a small bell trans- 
former, connecting the microphone to the 5\ 
output, and the amplifier to the 230V input. ■ 



August, 1964 



PRACTICAL WIRELESS 



371 



DO IT YOURSELF 

Build a Record Player and Save Pounds 

The Cheapest Way The L.K. Way 

# SCOOP iTransistor Tape Recorder. The best obtainable TRANSISTOR SECTION 

by very famous manufacturer. Brand new, boxed, guaranteed. # SCO OP! A first-class 2 wave-band 6 transistor superhet 

Reduced from 12 gns. OUR price £7.10.0 P. P. 3/6. Complete chassis by world famous manufacturer. Fully built, aligned, 

with microphone, tape batteries and operational booklet. tested, guaranteed. Full coverage long and medium waves. 

Features push-pull amplifier, two motors, single switch opera- Note OUR price £4.4.0 only. Suitable speaker 10'e. A few 

tion, pause, speed, wind, rewind, record, play back. Can be cabinets can be supplied at 22'6 each. OUR price for the 

used in any position, indoor or outdoor. package dea! £5.5,0 only. 

Famous Autochanger or Single Player Units supplied with • SCOOP! As above, 7 transistor 

brand new, two-tone, de-luxe portable cabinets. 17 x 15 x 8£in. OUR price £4.15.0 only. Suitable speaker I0'6. Cabinet 

strong carrying handle, gilt finish clips and hinges are used by (very attractive). 22'6. 

famous make for 22 gn. model. Ready cut out motor board OUR price for the package deal £5.14.0 only. 

14 x 13m. Front baffle 7 x 4in. High flux loudspeaker and 3 watt • SCOOP! As above. 8 transistor. 

amplifier. Amplifier ready bu.lt on metal chassis with output OUR price £5.4.0 only. Suitable speaker I0'6. Cabinet 

transformer, volume and tone controls. All items fit together (very attractive two-tone) 22'6 

perfectly. Assembly in 30 minutes. Only 5 wires to join, 12 OUR price for the package deal £6.10.0 only. 

months written guarantee. Available separately or package ©SCOOP! A Limited Number Only. Tape Decks by 

ft mcJS «'*,. c .. r BSR ' Late « model. A.C.-200,240v. Brand new and boxed 

Our NEW MKI1 Superb Kits are now being dispatched. OUR price £6.0.0 only. P.P. 4'6 

L K PRICES FOR COMPLETE KITS: • SCOOP! Tape Recorder Amplifiers. Suitable for 

Autochanger Kits as above BS R > or Collaro Decks. Price: £6.10,0 for B.S.R. Deck; 

B.S.R. U.A. 14, T.C. S Mono £10.17.6 P.P. 5'6 '6.12.0 for Collaro Deck. P.P. (,<-. 

Garrard Autoslim, Mono £II76PP 5'6 Mk.lll. Fully built, high gain, low noise, printed circuit. Attrac- 

Single Player Kits as above £? f f y and gold front panel 1 13 x l|in. Overall height 5*in. 

Garrard top in Mnn« *•« ii i nn r i* front- to back measurement 5jm. The amp hfier is supplied 

f$fi3£z2ft8E > ...::::::::::::::::::::::: t&lttft It r ? p ™JJV^ r tch r ( v *£lt*® ^ B .s. R '!**. 

Individual Prices for those who wish to purchase separately InL^Zluh m™^*^?? se P arato switch with 

Record Player Cabinet with Cut-out Board .£2 1 SO P P 3^6 *!' ei « «»P P « J' C . .E DM? ° f '" ed ' 

Amplifier with 7 x 4in. speaker . £3 PP 2/6 • SCOOP! Superb l?64 F.M.- M.W.-S.W. 3-Band 

. „ . ".■u.vr.r.xo Radiogram Chassis with F.C.C. certification. Frequency: 

a c <? C , i^'/'t ^- a « t M - 88 -' 08 Mc s: B ' C - "5-I60S kc/s; S.W. 3.5-9 Mc/s. Output, 

B.S.R. U.A.I4 T.C. 8 Mono £5.7.6 P P. S'fi 5 watts, A.C. only. Ferrite rod aerials. Product of very famous 

Garrard Autoslim. Mono £6.0.0 P.P. 4'6 manufacturer. Brand new with full maker's guarantees. 

Single Players List p ice 22 gns. OUR price IS gns. only. P.P. 5'6. 

E.M.I. Autostop, Mono £5.7.6 P P 4'6 FREE! with this superb chassis for one month only, two 

Garrard S.R.P.I0, Mono £5,5.0 p!p' 4'6 S x 6in " P M Dynamic Speakers and beautiful cabinet with 

E.M.I. Separate Pick-up £3 P P 3'6 matt chrome trim. Knobs are included to suit the chassis 

Transcription Units— Stereo Head— Mono a' 6 "? *f nd l°- our Ct l a | sis Lis ^, lh -?' f are FR1E - Wc are Mai " 

Garrard 4 H.F. Stereo £14 Ifl P P 5 f Ag<mts ior Brltcamer Empress" Chassis. 

Philips A.G. 10/16, Stereo ■•■■■•"■ ^ ^ p . p . a + SCOOP! Complete I4in. TV Sets— Untested. Choice 

Garrard A.T.6, Stereo .., £9 |y'* p'p" si of p V e - Philips, Ekco and Sobell, well packed — but at 

• crAnpi r c t> i i a i4 a .. "' t-z- '= ^ "... owners risk. £2 each. Also few 17m. TV sets £4.10.0 each. 

RrJnd «w J ** V' d 4 A J U { t0ch * nge "J C t. r ? " PU - Plu * carnage and packing inner London 10'-. elsewhere 15'-, 

Brand n ew and boxed^ Wired for stereo. Note OUR price VALVES-Ex-equipment Tested and Guaranteed 

• SCOOP! Garrard Autoslim Mono P. U. Brand new MrSoft KTHC E SyS? l\ «!, X,\ ^ IJ- 
and boxed. Wired for stereo. Latest model. EBF89 4tt KTSfi 7( PYRT v ^r? 2 /. 6 ??„,;, 

^ftft.,^"- - 00 " 1 ^ pps '- EOTii! pclitll: ptII 11: till - u" If: 

X 1 ?£ ° op! Diodes— over 1,000,000 in stock— ideal substitute ECCS2 4'- PCF30 4'- PZ30 T- Tt\l It 3SZ3 5'- 

O.A.81 vision detector. ECC8S 5'- PCF82 4'6 U2S 6'- 3SZ4 SI 

Note OUR price £1.0.0 per 500, P.P. 2'-. (In 500 lots only). ECH3S o'- PCL82 5'- U26 6'- tf\* 6 '~ 30PLI 7~- 

• SCOOP! 3-watt Gramophone Amplifier. Complete ECH42 6'- PCLB3 5>6 UI9I T. ° L ' 7- pL|2 
with 5in. Speaker, 49'6. P.P. 5'-. ECH8I 6'- PCLB4 6'6 U30I 9?- 6UIS 7 '- 30PLI3 6'- 
The amplifier is complete, on a fabric-covered baffle board ECL82 61- PL33 7'- UAF42 5'- 6P15 s '" 30FLI 7'- 
Output transformer included. Tone and volume controls and EF8S *'* PL3 6 6'6 UBC4I 5'- 6P28 8'- 6/30L2 T- 
on off switch. Ready to switch on and play. Terrific volume EF91 2 ' 3 PLS ' S'6 UCC847'6 7B6 6'- rjo &t 6 
Sue I2iin. x 6in. x 3^in. back to Iront. For 200-250 v. A C EL33 s '- PL82 4'- ECF80 7'6 7C5 6'. 50CD6 
Output 3 watts. EL84 5'6 PL83 5'- UF42 2'6 7S7 I0 f - 16'- 

• SCOOP! A Stereo Amplifier by world famous amplifier | Y j" }'' PY ^ J!« 6C9 10'- 7B7 6'- 6CD6G 
designers. S watts per channel. Facia panel in black and silver. E Y86 4 6 PY33 ' * 6XS 4 ' 6 7V4 s ' m «'- 
Assembled, tested, guaranteed. Even leads and plugs supplied EFB0 in a bat ch of 12 for 16'-, plus 2'6 P.P ECL80 in a batch 
Maker's package unopened. of 6 for 14'-. P.P. 2'6. P.P. is fid. on each valve. 

OUR price £7.(0,0 List price £15.15.0. P.P, 5'6. Mullard I4in. tubes of all types. AW and MW. All I7'6 each. 

Please send for our Amplifier and Hi-Fi lists they ore FREE. Our pp - ,0 '- 

prices the mast competitive in the trade. Speakers ex Equipment. Sin. S'; 7in. x 4in. 6'-, 6in fi'fi 

• SCOOP! Microphones Complete Lead Coax. Plug, I'l" L'"" PP '.'! 6 each - 

Brand New. Our Price. S'- only. P.P, l'6. S. A. E. enquiries please. Our Complete Lifts I'- only 

—credited against your order. 

• IF NOT ADVERTISED IT IS STILL IN STOCK ■ THE CHEAPEST THP rcct tue qiih-u-cct 

• MAIL ORDER ONLY TO THIS ADDRESS PLEASE SERVICE. * ' QUICKEST 



L.K. ELECTRONICS (Victoria) LTD 



27 OLD BOND STREET, LONDON, W.I. 



372 



PRACTICAL WIRELESS 



August, 1964 



CONSTRUCTORS BARGAINS 
THE 'REALISTIC 7 jgSZS^^^ 

Transistorised Portable Receiver f 

mad e to t he h I shes t prof essional staa- Kn 

dard. Comprises 7 Milliard Trans. HH 

plus Crystal Diode. 350 milliwatt out- g— 

put to 4in. speaker.— I.P. frequency f 

470 Kefs.— fully tunable over medium H 

and ion? wavebands. Two-tone plastic «g 

cabinet with handle— size 7x10 x 3lln. t..,, 1 

fitted socket for car aerial Complete •■•-■■. . . - . 

with full Instructions. .'..niitrii 

MAY nv. BUILT feiOC AU MrtSSOM separately 

POK ti0.i».D Bat t fry 3/9 extra, 

P. * P. 4« extra. (Circuit diagram 2/6. free if all parts bought.) 
AJ«wt DeLuxe Model with superior PVC covered wood cabinet 
and full view tuning dial. . „.,,.. 

Aui v *1 CYTRA All parts sold separately 

O NLY fel HA I KM Battery 3/9 extra. P. A P. </ » 

"THE SPRITE" 

8 transistor mini pocket receiver. Full L- J""* M. waveband 
coverage. Siio only 4 x 2i x lin. In sub assemblies. 3in. spaakor. 
■ * N BK TO d leather case, ear- -i o C 

BLILTfor '3» Phone «n<l battery ■ */*» «tT« 

All |>n rts sold separmHy. P. A P. 3/6. 

SUPER AMERICAN TAPE 

LAFAYETTE BRAND, FULLY GUARANTEED 
RECORO LOW PRICES 

uvi iR n.\«F ACKTATK BASE 

ftte. Double Play, l.WM*. 15/- 51n. I*ng pl»". WMt. 10/- 

5iln. Long play. 1. 200ft. 15/- 5lln. LonK play, UOWt. 12/6 

Siln. Double play. l.BOOft. 2SW6 TJa^^lfe^iSS 1 - 15/ * 

7in. Stand, play. 1.200ft. 12/6 MKSBSAX.fc TAPfcA 

to lSSpCS 1.300ft. 19/8 31n .-lSOft .3/6 

Tin! Double play. 2.400ft. 85/- 31 n.-MM t 4/U 

PVC R \SK 3ln.— 300ft ■,--.'•■ „/'* 

Sl'n. Standard play. 600ft. 8/6 Full rimfje of Triple Play 

6|ln. Stand, play. 850ft. 11/6 lupc »™''»^ pllll 
P. & P. 1/- extra per reel, i reels and ovr Pogt Free. 

WIRECOMP ELECTRONICS 
378 HARROW ROAD, LONDON VV9 

TEL: CUNNINGHAM M30 

Hn.ir- of business: 3 a.m. to • p.m. °Pen all day 
Saturday. Opposite Paddlngton Oeneral Hospital. 
' kijm's IBB and 36 pass the door. 




Boy's 2 Transistor Pocket Radio 

h$i)&&Mm% Readv made as illustrated— complete with 
■?.$ personal earpiece, telescopic aerial, battery 
a and carrying case! Wonderful value and per- 
formance—full medium waveband coverage- 
built in 211n. speaker gives full tone reproduc- 
tion. Works on single PP3 8 v. battery, in 
attractive plastic case— sire only 4 x 3t x lln. 
All accessories included in ths price. Not a toy. 

WIRECO.IIP'S £«/_ POST 
PRICK COMPLETE *•* FREE 

Also ti transistor model. Lone and medium waveband. Fully 
built complete with earpiece, batten- and leather ftO/'C Fost 
carrying case. vtr l " Free 

HMV 40 r.p.m. AUTO RECORD PLAYER 

Takes only 45 r.p.m. Tin. discs. Plays 
up to 8 automatically. Fitted with 
lightweight pick-up and crystal car- 
tridge. Mounted on sturdy plinth—^ 
size 10 x 10 x 5in. For 300/250 v, A.C. 
mains. WIRECOMP" s CQ;6£-*I\ 



!MM1V TRANSISTOR AMPLIFIER 

Suitable for use with the abOTe 
changer. Battery 2/8 extra. 
WIRECOMP'S 35 /,- r kp - 



PRICE 



Bffl 




Suitable 9 x tin, spi-aki'i- 13 /6 Post Free. 

The transistor amplifier can be Incorporated In the plinth of 
the changer with the speaker— thus making- a self-contained 
Record Player. £E Q ft POST 

Can he pun-haseil 1<m-th«*r for **»*»^.v FREE 

Transistor BABY ALARM INTERCOM. 

In 2 compact units, each size 4in. x24ln.x iin. Internal loud- 
speakers Give ample volume. Complete ready (or immediate use. 
Works from PP3 battery. Complete with battery and sixty 
foot of connecting- win. ftQ ft P. & P. 2/6. 
WIRECOMP'S PHU l: W.'P 

Transistor TELEPHONE AMPLIFIER 

A must for business or pleasure. This neat little transistorised 
amplifier powerfully amplifies the incoming call and at last 
leaves you with both hands free while continuing your con- 
versation normally. The pick-up is suction fixed to phone. 
Batterv-operated at negligible cost. Fitted off switch for 
private conversation. Size 41 x 3 x llln. Complete with battery, 
WIRECOMP'S PRICE CO , ft 

DST'O P. & P. 2/6. 



NORCOL LTD. 

wish to announce their latest developments 
shortly, 

TRANSISTOR TOP BAND Tx 

8 watts Carrier Power. 12V h.t. 

70ft aerial output. 

KIT complete with microphone, 414. 

TRANSISTOR TOP BAND Rx 

lu.V in for 200mW into 3£1 speaker. 

12V h.t, t.F. 455 kc/s. Tunable 

1.8-2.0 Mc/s. 

KIT complete, £10 (covers broadcast 

band). 

TRANSISTOR RADIO batteries are expensive. 
The NORPACK miniature battery eliminator 
pays for itself. Approximately 4± x 2£ X 2in. 
9V O.'P from mains. KIT complete, 35'-. 

An Alignment Service is available for assembled kits. 
NOMAD Car Radio still available. £4.19.6. 

PJeose send S.A.E. or phone for more deto/ls: 

PHIL SMITH, (G3PPU) Shop Manager 

147 LONDON ROAD, CAMBERLEY, Surrey 

Camberley 3743. 



Amatfub pA 



CHAS. H, YOUNG LTD. 



DID. 



AERIAL EQUIPMENT 
TWIN FEEDER 300 ohm twin ribbon Ueder.similar K25, 
6d. per yard K.35B Telecon (round) l'« per yard. po« on above 
feeder and cable I '6 any length .„„«.» tit 

COPPER WIRE, I4G., H/D 140ft. IT'-; 70ft. »f«, P.* P- Vi, 
Other ten k ths P f o rota. 

AERIAL INSULATORS, Shell type. Sin .?d. Plus PosU 4 e. 
CERAMIC FEEDER SPREADERS, 6in. type F.S. lOd each, 
p a p 2'- 
CERAMIC "T" PIECES, Type A.T. for centre of dipoles 

^UeTER^BEAM I ELEMENT W.S. YAGI. Complete in 
bo" with l-liin. mast head bracket. PRICE «'- P. * P. 3'6. 
SUPER AERAXIAL CABLE, 7S ohms 300 watw very ow 
low I'fl per yard. P. & P. 2'-. SO ohm, 300 watt coax very low 

AB%ORPTION*WAV6METERS 3.00 to 35.00 Mc/s in 3 
switched bands. 3.5 7, 14, 21 and 28 Mc/s. Ham bands, marked 
on scale. Complete with indicator bulb, A MUST for any 
Ham shack, 22'6 post free. 

VARIABLE CONDENSERS All brwi with Hniiiicind 
plates and ballrace bearing. 50 P F. Sf, 1 00 pF, •'*. 160 pF, 
7 f 6 240 pF 8'6 and 300 pF, 9-'« All fitted with roar extension 
for'zangine. P. & P. I'- Also Flexible Couplers, I'- each. 
SETS OF VALVES for AR88 (H) £3.10.0 poat .free. 
METERS. 3iin. with 2»in. scale, 0-10 mA. II'-; 0-100 mA. If'-. 
P & P I '6 
THERMO, 21in. round 0-2.5 amp, 7'* each. P. & P. I'*. 



170-172 CORPORATION ST. 
BIRMINGHAM 4 

Telephone CEN 1 635 



August 1964 



PRACTICAL WIRELESS 



373 




rade 



ews 



Two in Tune 

JTEATURES of the two latest transistor portables 
from Baird, are their light weight and neat 
design. 

Model 290 weighs l-}lbs. with PP6 battery, 
covers medium and long waves and employs seven 
transistors. Tt has a 3in. speaker, aerial and earth 
sockets and tape recorder /earphone socket. The 
brown fibre case is covered with foam-filled 
leathercloth and measures 7r B in. x 2in. x 5in. 
Price is 1 1 guineas inc. P.T. 

Model 292 weighs 21bs. with PP6 battery, has 
seven transistors and covers medium and long 
waves. Like the model 290 it has a 3in. speaker 
and tape recorder /earphone sockets. Provision is 
also made for the attachment of an external aerial 
and earth. 

Housed in a deep grey leather grain plastic case. 
model 292 measures 8+in. x Hin. x 5in. Price is 
10i guineas inc. P.T. Baird TV Distributors Ltd., 
414 Chiswick High Road, W.4. 





This new capacitor tester is made by KLB Electric 

Limited. 



In-Cireuit Capacitor Tester 

^HE PACO C.25 "In Circuit" capacitor tester 
is described as one of the most valuable pieces 
of fault-finding equipment that any service 
engineer could have on his workbench. It reveals 
immediately any open or short-circuited capacitors 
without removing them from the circuit. The 
PACO C.25 also locates dried-out electrolytics in 
one quick test. Price is £15 19s. 6d. complete, or 
may be purchased in kit form for £14 12s. 6d, 
KLB Electric Limited, 335 Whitehorsc Road, 
Croydon, Surrey. 




The model 292 transistor receiver new from Baird. 



the Danetcne 

Danish Record Player 

J^ROM Denmark comes this new Danetone SRT 

620 Hi-Fi mains record player. Typical of 

Scandinavian design, this record player is styled 

for use as a portable unit, and its black base and 



374 



PRACTICAL WIRELESS 



August, 1964 



teak coloured wooden top make it a very attrac- 
tive accessory in the home. 

Features include autostop mechanism. 4 speeds, 
stereo cartridge, tone control and 2fW virtually 
undi stoned output into an 8 in. speaker housed in 
an acoustic wooden cabinet. 

The Danetbne SRT 620 costs 21 guineas inc. 
£3 Is. purchase tax. An additional matching 
loudspeaker for stereo is available in a cabinet 
with extension lead supplied, at an extra cost ot 
7 guineas. Denham and Motley Ltd,, Denmore 
House, 173/175 Cleveland Street, London, W.l. 




TWs new french receiver has recently become available 
in this country. 



Portable Car Radio 



The valve line-up is: EF80/EF80/6BW6/ 
12AX7/6BW6. and the power requirements are 
250V, 100mA: 6-3V, 1-8A (or 12V, 0-9A) 150V 
stabilised for VFO supply. There is a matching 
power pack for 200-250V a.c. . 

Also included is standby /net /transmit switch- 
ing, together with aerial changeover, transferring 
the aerial to the receiver in the " standby posi- 
tion Neon indicator monitors " standby and 
" transmit ". Price of the transmitter complete 
£16 10s., and the power unit, £8. Codar Radio 
Company, Bank House, Southwick Square, South- 
wick, Sussex. 



TO COMPANY announce a new 
the A.T.5. The dial is calibrated 
1-8— 2-OMc/s and 3-5— 3-8Mc/s, covering the 160 
and 80m amateur bands. At the rear of the 84 in. 
x Sin. x 4in. cabinet, are Mic. co-ax socket, preset 
mic. gain control, power supply socket, phone/ c.w. 
switch and output co-ax socket. 





the latest transmitter from Codar. 
Wonder Plug 
\ BOON to all servicemen and constructors is 
"~* the " Fittall ", a plug which eliminates the con- 
tinual changing of electric plugs to fit different 
sockets. Five types of plug can be made: 13A 
fused, 5A 3-pin, 15A 3-pin, 15 A 2-pin and 5A 
2-pin. All that is needed to change the plug pins 
being simple movement of the selector arm fitted 
at the base of the plug. The whole unit is housed 
in a shock-proof unbreakable plastic housing. 
Price is fixed at 12s, 6d. R. W. Rumble (G.B.) Ltd., 
Coastguard Road, Larne, Co. Antrim, N. Ireland. 

WARNING: LIVE CHASSIS 

With reference to the article a "Voice-operated 
Baby Alarm" published on page 253 of the July 
Practical Wireless, we bring to reader's atten- 
n that the chassis in this design is connected 
inertly to one side of the mains supply. It is 
'ercfore possible for the chassis and the micro- 
one to be "live," presenting a danger of shock 

the user. ... . 

ertain modifications should thus be earned 

t to render the equipment safe. The fitting of 
,J2f»S 1,000V d.c. capacitors in each of the leads 
o the television receiver, and also in the micro- 
phone leads before they leave the chassis is 
recommended to readers intending to construct 
this piece of equipment. 

Contact with the chassis should be avoided, 
and no attempt should be made to "earth" the 
equipment. It is further recommended that the 
equipment is contained in either a wood or bake- 
lite type cabinet to reduce the risk of shock to 
others. Any fixing screws that appear on the 
outside of the cabinet should be carefully 
"hidden" or covered. If a slight "shock" is 
experienced when contact is made with the micro- 
phone, either the mains lead to the wall plug 
should be reversed, or the plug itself. 



August, 1964 



PRACTICAL WIRELESS 



375 




TAKE 




Brochure p 
LIGHT 



There are 30 other models, too. There Ah t severa, otner makes of solder- 
ing instruments. Big ones. Small ones. Good ones. We've seen them. We 
don't make the biggest ones. Or the most expensive ones. Or the most 
elaborate ones. We DO make the smallest ones. And the widest range. 
We make the best. Always have. May we send you details? 
W. 1 post free on request 

SOLDERING DEVELOPMENTS LTD., 28, Sydenham Road, Croydon, Surrey. 
^ ^ Telephone: CROydon 8589 



WEYRAD 



TRANSISTOR COILS 



Tr^„ s ift°="s r uV«S:- the m °" <""""" *"" Wide " USed "™l»n.a B for M«di„m Jn d Lon g -w a »e 
P50/IAC Oscillator Coil for 176 pF tuning 
P5Q/2CC 1st & 2nd I.F. Transformers ... 
P50/3CC 3rd I.F. Transformers 

daiia/^" r7 ? ou !? ted in individual cans |±in. 'diam]"x Jin. "high. 

RA2W Fernte Rod Aerial 208 P F Tuning 

LFDT4 Driver Transformers [[[ 

OPTIA Output Transformers ... "] 

PCAI Printed Circuit Panel ... 
Constructor's Booklet 



S'4 ea. 
ST ea. 
V- ea. 



W6 ea. 

9 '6 ea. 
10 '6 ea. 

9tt ea. 

21- ea. 



VALVE RECEIVER COILS 

Sceiverl V She^m y |^r T°R P° re , d ^ ?" With ° Ut eqUa! for the ^""ruction of a wide range of 
coils 3% i2 T k T a /' • se f cover| ngoneor more wave-bands the Aerial and H.F. Transformer 
coils are ideal. The standard superhet circuit using the ever-popular triode-hexode frequency chan« 
layout would employ the Aerial and Oscillator coils and the coverage can be selected f rim 7 different 
,*& h angmg f T i 2S \°3^° metreS " For a rea ^ high-performance rece ver an R Ttage can il 
such a f^youT lhe Aenalt H - F - Transformei - "d Oscillator Coils and a circuit is provided Stratin 

H Coils 3 '9 each. 

WEYMOUTH RADIO MANUFACTURING CO., LTD. 

REGENT FACTORY, SCHOOL STREET, 
WEYMOUTH, DORSET - 



376 



For 

HIGH SEHSITIVITY 

MAXIMUM RELIABILITY 



PRACTICAL WIRELESS 

LINEAR 



August, 1964 



HIGHEST FIDELITY 
REASONABLE COST 



We regret to announce that after maintaining our prices for seven years (with 
the exception of one unit) we are reluctantly announcing a revised price list. 

LT.45X. Tape Amplifier with equalisation adjust- 
ment for l£, 3f- and 7£in, per second. Suitable for 
Collaro Studio Tape Transcriptor. Complete 
with intregral power pack. 
Retail price I2i guineas. 



L.50. 50 watt Amplifier approximately 14x10x8 in. 
Sensitivity 25 m.v. output for 3 and 15 ohm 
Speakers. Retail price 22 guineas. 

CONCHORD. 30 watt Hi-Fi Amplifier with two 
separately controlled inputs. 
Retail price 17 guineas. 

LIO. 10 watt Hi-Fi Amplifier with separate pre-amp. 
Retail price 16 guineas. 

L.I/10. 10 watt Hi-Fi Amplifier with integral pre- 
amp. Retail price I3| guineas. 

DIATONIC. 10/14 watt Hi-Fi Amplifier with 
integral pre-amp. Retail price 12£ guineas. 

L.5/5. Stereophonic Amplifier. Output 5 watts 
each channel. Retail price I2£ guineas. 



LP. I Tape Pre -Amplifier. As above but less power 
pack facilities. 

L.45A. 4/5 watt Amplifier. 
Retail price 6 guineas. 

LG.34. 3.4 watt Amplifier. Shelf mounting type 
for gram use. Re toil price £5.10.0. 

TREMOLO UNIT. For Guitar purposes to plug into 
mains Amplifier. Retail price 4 guineas. 



Trade and Export Enquiries invited— ,,,«,.,„,. , 

I IMEAR PRODUCTS LTD ELECTRON WORKS Tel. Leeds 63-0126 (3 lines). 
LINEAK rKOUUVI) LIU. ARM LEY, LEEDS. S.A.E. for catalogue. 



SUMMER CLEARANCE SALE - PRICES SLASHED 



STOCK ROOMS MUST 
TO MAKE WAY FOR 



MAKE5DJFFFRENT 

TRANSISTOR 

RADIOS FOR 30/- 

vmazlnt: Radio Conetnicton Set: 
, llecnmi: a rtldlo expert I'or 30,'-. 
'. . nni'ti' Home Kaiilo Course. 
no eJtpcrlt-nce nenrled. PartB 
■uuk. InMnKtlous for 
each dedfctt- s-l.p-Ly-Sl-iSp PIBD, 
all Transistors, tuud*pi , 3ii--r. persiiual phone, knobi- 
■crews. etc.. ad you need- Box .ize 14 x 10 x 2ta 
(££-£, avail sep-)- Orittliially «, 30/-, phis- tt/S 
F. A P. 






MINUTE 

TRANSISTOR 



17/6 



Amaze at the quality 
of tone and volume. 
Si x B| sr Hin., the 
MIAMI works for month* on a MM. battery, 
Simple aewmbly plan with set, 17/8, plus 1(8 I*. * P. 
All part* available separately. 




MINIATURE SPY CAMERA 

OSLY -(9/0 

This exciting little J- 
speed camera Is a pre- 
cision-made Instrument 
in dirtmird steel and 
leather with mflll-utac.nl> 
•■-■Hi I :■>■!.— rath 'I i .in I '" '..la- i' i ■. ?"■'•■■'- 
11 x 11 i 2in., only 18/8. P. ■* I*. " «J»* 
FREE Leather Cerr»-«a*s. Six Bolls ot Film. 

"VOLKSRADIO" 

POCKET VALUE RADIO 

15/- 

Take-over Bid makei thii 
Fantastic Offer possible - 
tile beautifully compact 
"S Star Volknadio" mea- 
sures 4J x. '2\ x IJiti. 
receives perfectly — In ktlfl 
bedroom, office, garden 

over all M.W. incl. Li-ncmo'-urg. Undot Id. lion 

running cost. Anyone can assemble It In 1 o 
a hours, using our aiiuplo A. B.C. plan, 1W-. idus JJ 
P. t P (Parts can be bought eep.) 



ONLY 




Our New 4-Stage 

Kul Id this new I y de sign cd r 
"HINTJETTE" a-STAGE 
transistor Bet In vi-ry 
-drone, ready drilled 
ILfllA MODEBS 
( AS];, KUe only Hills 
I In. i-'ses three transla- 
tors anil diode ftttd 
9E I.C-iONIAIS BO 
LUi'if-l' LAKER. Very 
i. holidays, civ. 
Ustenin.il off a 1/2 Itnlt 



BE CLEARED 
NEW STOCK 



MINUETTE 




OffiCA 



KtltikS of 



ensitive. (ilea 
Uonitu ukd 

....... can be built FOB 

ON LV 38/- Iticudintr Proper Case, mini a tin 

ate. Simple as A.B.C. Pictorial Step-by-Step Plans, 

etc., plus post and packiiiK US. Parts sold separately. 



AMAZING CIGARETTE RADIO 
ONLY I8'6 NO MORE TO PAY 

Amaze your Irieadtl this 
hcnlv sensitive TRANSISTOR 
"CIGA-RADIO"' reciven all 
icdlum wave Rtatiun* clear 
*d ensp — holds ten age. — 
..elglis less than » " 
ciga.l Tiny battery Inside costs 
3d. lasia over 3 mouths. This 
brilliant little novelty persona) 
•phone Tadio is ideal lor Bedside, Newt, Sporti, 
Office fan be built by anyone from pictorial 
diagrams In an hour or tiro. All parts supplied 
lor 18/8 (add 1/6 P. 4 P->- (Farts sold sei-aratelyi. 




Fabulous ST. TROPEZ MK.6 
The Sensational Pocket Radio 

- raw Thl» I'milttttlc oiler will amaze, yoii 

i- ' ffTl —the beautifully eornpitel ST, 
1 kVii H TROPEZ, measuring -U X 3 x l}ha. 
iicrfcctly Id bedroom, ■ 
office or garden — over all nudlum 
wave* Including Luxembourg, ru- 
der 14* per hour running cost. 
AHYONE can assemble It In one J 
ar («■! hours using our simple | 
A. B.C. plan, 251- Of- -• P. -■■t> 
(Case extra). Parts can be bought Boparntely, 

Bnuwl Hew, Boxed. ATTTOHATIC CAB ClttAHETTE , 

LIGHTERS. Heavr chrome fltliah, holding 10 d«s. 

and ftisuca ready-Ut dc. Works oft 1 or 12T. \ 

Special Clearance Friee 10/8. plus 1/* P- * P- 



TRANS1ST0R POCKET RADIOS 

BOLK PURCHASE ViiSABl.ES US 
TO MAKE THIS rASTASTIC 
OFFER- AND WITH MOSEY 
BACK UITARASTEE ! ' The 
s.w RKMO i ,i«o tuned that it 
brings the voiesa ot »iar enter- 
'aitim's a nil vocalists dramatically 
iu tijfg — in your home, office, etc. 
rjnrj it * ?i * It'"- ! '■ 
Into your pocfeet or handbag. 
Works for month* ofl lit battery. Should ln-i a life- 
time, anyone can asM-mlde It in an hour or two with 
am ••*? plan. >!:...■:: b|iuaiEei carrjdnl ■■-<-■: — 
everytbing only 88/B. S'a F. * P. (Paru ««- •» 
bought separately d 




READY T 

TRANSISTOR RADIO 
FCLLY TRANSISTORISED 
SKYR0MA Mk. 7. This 
la U i-l IBS! model » 
cheered by experts tor IM 
tmitasiicaily low 1-™ , |'. 
Hullt In two-tone ewe, she 
41 x 21 Jt litn. Ki'.^lvu 
M.W, stations loud and 
char. Every radio Is full* 
tested before diFpalch. 
Price ready built 86/-. I'. I P 
lii.MtB. Free earpiece wit I 




FOR OHLY 

25/- 

^0 more to pay 



CONCORD ELECTRONICS 



LTD. (Dept. P.W.I 0) 9 Western Road, Hove, Sussex 



August 1964 



PRACTICAL WIRELESS 



377 




PRE-WAR FIELD DAYS 

gIR.— Before [he last war I used to belong lo 
the "Thornton Heath S,W. Society", now 
defunct. Some of our members were G2RD, 
G2DP, G4AA and G4FW. but I had only reached 
the 2FXT artificial aerial licence stage. 

In June, 1938, we had a 5m field day and I 
partnered G4AA. We found a beautiful spot near 
Warlingham. off the beaten track, with no 
screaming jets flying over, just an occasional visit 
of a stately Hannibal. 

We settled down to logging the various stations 
till about 2.30 in the afternoon, when we 
discovered that our beer had run out. We tossed 
up to see^who would make the trip to the nearest 
" boozer " some two miles away and mv partner 
lost, so away he went, leaving me strict 
instructions about the liveliest part of the band. 

After logging several stations I turned to one 
end of the band and could hear music, classical 
music: appropriately enough Beethoven's Pastoral 
Symphony. I opened the back of the set 
stretched the coil a little, and heigh ho. there was 

Ally Pally " spot on ! 

1 listened on and on to the orchestral concert. 
Suddenly a shadow appeared over my shoulder. 
It was my partner, who had been lucky enough to 
get a lift back by car and so arriving back a lot 
quicker than I had expected. Was my face red 
and was he mad! Needless to say, we finished 
well down the field at the end of the day. 

I often wonder what has happened to all my 
acquaintances since then. But one I do know and 
often hear him, Alvar Liddell. In those far-off 
days Sunday mornings used to be a busy time and 
even 2FXT used to "jump" the artificial aerial, 
but nowadays I think the bands seem empty of 
local 'phone stations. — P. O. Hubbart (West 
Croydon, Surrey), 

(Out of those licensed amateurs mentioned by 
Mr. Hubbart G2RD and G3FP are known to be 
still operating, — Ed.) 

A NOVEL ECHO UNIT 

gIR, — I wonder if any of your readers have ever 
tried the arrangement that my friend and I 
used to obtain an echo. The quality is by no 
means hi-fi but is suitable for a lot of "science 
fiction " music. 

One tape recorder containing the loaded spool 
is set to "record " and the other is set to "play ". 
The first one's microphone is placed near the 
second one's speaker. This system has one 
serious drawback, though: the distance between 
the heads is too great for an echo. However, if 



Whilst we are always pleased to assist readers with their 
technical difficulties, we regret that we are unable to supply 
diagram* or provide instructions for modifying commercial 
or surplus equipment. We cannot supply alternative details 
for receivers described in these pages. WE CANNOT 
UNDERTAKE TO ANSWER QUERIES OVER THE TELE- 
PHONE. If a postal reply is required a stamped and 
addressed envelope must be enclosed with the coupon from 
page iii of the cover. 

The Editor does not necessarily agree with the opinions expressed by 
his correspondents 



the first recorder has its pressure pads held off 
the tape, and the tape is guided over the record 
head, the second tape recorder can be put on to 
" fast rewind ". Upon pushing the tape on to the 
head it will play. The effect of the increased 
speed is the same as decreasing the distance 
between the heads and so an echo is obtained with 
no additional equipment. 

When played on fast rewind on the second 
machine (now detached from the first) the echo 
can be recorded on the first recorder at a more 
orthodox, less tape-consuming speed. Incidentally, 
good effects are also obtainable by plaving the 
tape in reverse.— P. Riley (Croydon, Surrey). 

NOT SO OBVIOUS 

§ JR. —Regarding the 7Mc/s Transceiver fJune 
P.W.), it occurs to me that it might develop a 
little fault after a few weeks' operation. Those 
who have studied the circuit of the ex-W.D. No. 19 
will have found that almost all the decoupling 
capacitors in the "A" receiver are 350V wkg. 
The maximum voltage to which they are subjected 
is in the order of 250V. It will be observed, 
however, that the a.g.c. time constant /decoupling 
capacitor to the r.f. amplifier is of 600V d.c. 
working (provided the set is post-1942 or 
modified). 

Six hundred volts of a.g.c, does seem a bit 
much! It bothered the poor wireless mechanics 
in the early 1940's, too, until someone had the 
bright idea of putting a valve-voltmeter across the 
then 350V a.g.c. capacitor and switching to send. 
As the receiver heaters were left on when 
transmitting and only the h.t. switched off (as in 
the 7Mc/s Transceiver) the control grid, tuned to 
the transmitter frequency, acted as a most 
excellent diode, and the resulting voltage was 
usually too much for the poor old a.g.c. capacitor. 

I'm not sure how much transmitter voltage will 
be induced into the grid circuit of the triode of the 
receiver in the " Transceiver " as I have not built 
this circuit myself but I suggest some tests, are 
made — just to make sure about these voltages. — 
Mayday (name and address supplied). 



IR — The 19 set runs an 807 to some 25W input, 
30V at 50mA, whereas the 7Mc/s 



S 

Transceiver runs an ECL86 to some 5W input "and 
with a difference in power of less than a quarter. 
The corresponding voltage across the capacitors 
would be very much less. The receiver blocks on 
keying obviously because of the diode action 
referred to and I use this as an aural indication 
when I am sending. "Mayday" doesn't sav (he 



378 



PRACTICAL WIRELESS 



August, 1964 






value of the a.g.c. capacitor he's reternng to but 
in the grid circuit of the Transceiver the values 
are 2pF bandpass coupling and 300pF grid leak. 
I should therefore imagine that a.g.c. decoupling 
would be 005,uF or 50,OOOpF.— D. Gibson, 
G3JDG (St. Albans, Hertfordshire). 
Sir,—! would be grateful if any reader could sell or 
Joan me ... 

... any information at all on the No. 19 Set.— 
P I Peters, 59 Man vers Road, Swallow Nest, Sheffield, 

. . . any circuits, manuals, etc., on the Marconi 
Canadian No. 52 Set.— P. Woods, 46 Chaucer Road, Bedford, 

information dealing with modifications to the 
Wireless Set ' 19 Mk.3.— G. Faitnpel, 86 No Sudley Road, 
Liverpool 17, Lancashire. , 

the circuit diagram and instruction manual of 
the Collins TCS11 receiver.— G. Greenslade. 2 Millham Road, 
Lostwithiei, Cornwall. Mk-umi m inn 

the circuit and any data for the Marconi lkjuu 
receiver. All 'postage refunded.— E. Ford, 106 Skinner Street, 
Cresswell, Worksop, Nottinghamshire. 



service data or manual tor the Halliorancr 
Marine Radiophone. Model H.T.I 1 or 1 la,— K. B. U MaSUK.lr. 
"Atmir," heuure, Cobo, Guernsey. 

the manual or circuit diagram for the v.h.i. 
transmitter/receiver type TR1986.-K. OR-CHARP. 2d Kenmore 
Drive. Yeovil, Somersl. __ . ..,, 

, ..one clean copy of P.W for Dec^r 1962 
(with blueprint) for two clean issues of November 1962 (wuh 
WueprmS -R Tuppen, 122 Old Farm Avenue. S.dcup, Kent. 

the issues of P.W. covering the conversion ol 
the No. 19 Set (May and June 1958) -DU Hughes, Mountain 
Air. Began Road, St. Mellons, Nr. Cardiff. 

copies of P.W. for April, May and June 1961. 
dealina with the P.W. Signal Generator. All postage costs paid.— 
N Hum, 7 MarsVon Road, Silversands Caravan Park, Lossie- 
mouth, Morayshire, Scotland, - « „, * m „„ u( 

the April 1963 issue of P.W.— A _ Williams, 
24a Gwyddon Road, Abercarn, Newport, Monmouthshire. 

information concerning the frequency ranges, 
crystal frequency, power supplies, etc., and any other , n to rmat ion 
on the WI19IA Wavemeter.— W. BoURKE, 33 Victoria Surest, 
Ruiherglen, Lanarkshire, Scotland 

manual or any information on the LiSA vane 
Tester/Multi-ra'nge Meter, Model No .774/4. 774/5 or 744/4.- 
R Hickun, 13 Clive Road, Heath Park, Romford, Essex. 



Cabinet Care 



— continued from page 354 



quicker and easier to remove it and refasten after 
cleaning. Always use a quick-drying cement, 
fasten one edge, allow to dry, then stretch to 

The deeper scratch may be filled, as with shellac 
filling of woodwork, but this time a weld is necess- 
ary to make the filler hold. If the filler is a piece 
of similar plastic, this can be chipped to a fine 
powder, then pressed into the crack, moistening 
the inner edges of the crack with carbon-tetra- 
chloride— (CTC) which is the basis of most switch 
cleaners and a solvent for many plastics. 

Great care must be taken not to allow the C I C 
to drip on the exposed surface of the plastic and 
the filling should be such that it can be polished 
down to the normal surface. A break can be 
treated in a similar way. the raw edges of the 
crack being brushed with CTC and the parts held 
together until the solvent evaporates, 

End Fed Aerials 

— continued from page 343 

satisfactory. Tinned copper wire is more easily 
tapped than enamelled wire. 

Capacitor CI should be wide spaced and 
equipped with an insulated extension spindle. It 
can be lOOpF to 200pF. Spacing equal to that of 
the p.a. anode capacitor (CI, Fig. 5) is usually 
sufficient. For the h.f. bands, fewer turns are 
needed, so the capacitor is tapped equal amounts 
towards the centre of the coil, by transferring clips 
from A-A to B-B, etc., or by using a double pole 
rotary switch. .... j 

L2 is three turns, adequately insulated, and over- 
wound on the centre of LI. This number of turns 
should generally do for 3-5— 28Mc/s, but if the 
3-5Mc/s band is not worked, two turns may be 
used instead. A convenient length of 75J2 or similar 
co-ax goes from L2 to the transmitter pi output 

When the aerial is of such a length that it is 
I near a 4-wave, or multiple of i-waves. on at 
! bands, it may be connected directly to point C. It 



This is by no means a perfect joint, and can 
hardly be expected to take great strain, but gentle 
care will often save the cost of a new— and expen- 
sive — cabinet. 

Worn Screws 

Worn screw threads when self-tapping screws 
have been removed and re-inser:ed too often can 
give a lot of trouble. The common mistake is to 
use a larger screw. This is no good— for the hole 
must be exactly drilled to clearance first, or the 
plastic will crack. A better way is to make a plug 
of sleeving, to fit the hole easily and take up the 
slackness of the screw. 

Use pvc. sleeving, and slit it along its length, 
so that the screw can get a good start and as it 
tightens it will press the p.v.c. to the walls of the 
hole and ensure a good fit. See Fig. 3. 

Special plastic cements arc available, for 
different kinds of material, but a good general 
purpose contact adhesive is often as effective for 
both wood and plastic breakages, where no strain 
has to be placed on the mended parts. ■ 



is then only necessary to change the taps A-A. 
when changing bands. uJ-^ii 

If the aerial impedance is low on some bands 
(due to its length) the aerial should be tapped down 
the coil. This' is most easily done by moving the 
aerial tapping a turn at a time away from the 
centre, until sufficient transmitter loading _ is 
obtained. If possible, an aerial length that is fairly 
high impedance on all bands is recommended. 

If the tuner is in circuit for both transmitting 
and receiving. CI may be adjusted for maximum 
signal strength on the receiver. If the receiver 
aerial input impedance is low. and the aerial impe- 
dance high, an actual increase in signal strength 
will be obtained. . . 

Loading of the transmitter is accomplished as 
previously described, but as the transmitter is 
working into the low impedance of L2. C2 will 
need to be at relatively high capacity for the LI. 
bands. If a standing-wave indicator is used. It 
should be included between transmitter and L2. 
and tuning is adjusted for minimum reflected 
power. When an r.f. meter is favoured, it should 
be included in the aerial lead, not in the lead 
from transmitter to tuner. 



August, 1964 



PRACTICAL WIRELESS 
ADVERTISEMENT 



379 




No, 4 



A CHANCE FOR 
PHOTOGRAPHERS 



Completely built Micro- 6 sets 
are a rarity at head office which 
is why a couple of our secre- 
taries slipped into the test room 
to listen for themselves and got 
caught in the act by the works 
manager who had his camera 
handy. If you have any amusing 
or interesting pictures of the 
Micro-6 in use. let us see them. 
3 gns. will be paid for each one 
published. Brief details should 
accompany each print sent. 
Unused photo* will be returned 
to readers. 



NEWS 



JULY/AUGUST 1964 





■ 



DESIGNS WITH A PEDIGREE 



It is but little more than a year ago that the name 
Sinclair Radionics appeared to the public for the 
first time, offering entirely new concepts in micro- 
radio receiver design. The impact was fantastic. 
There had never been anything like it before. Various 
other ^ designs were introduced, leading up to the 
world's smallest radio, the Micro-6 and then the 
TR 750 Power Amplifier. Today, Sinclair is the best 
known and most quoted name in anything to do with 
transistor designs for constructors. 

There are two simple, but exclusive principles 
behind this triumph— firstly the extraordinary effi- 
ciency of Sinclair Micro Alloy Transistors (Golden 
MATs). These make possible standards of perfor- 
mance far ahead of anything the public can obtain 
from other transistors. Secondly, there are the designs 
themselves. These come from a team accustomed to 
working to very high standards in transistorised 
electronics, for this group is but part of Sinclair 
Radionics Ltd. who are in fact industrial electronic 
consultants! 

So we are well used to solving problems and every 
design we produce for you is exhaustively tested long 
before being advertised. That is why Sinclair Micro 
Transistor Designs have completely captured the 
imagination and enthusiasm of constructors every- 
where. They have never had the chance to build to 
these professional levels in the transistor field before, 



to say nothing of the pleasure and satisfaction to be 
obtained from their wonderful performance. 

There are other intriguingly efficient designs using 
MATs which are well worth trying. These will be 
found in three books advertised on the following 
pages. In the meantime we learn that a number of 
constructors wearing Micro-6 receivers on their 
wrists, on being asked the time have replied with a 
somewhat far away look, "Half past Housewives" 
Choice" or words to that effect. Why not? The 
Micro-6 on its "Transrista" Strap is setting a new and 
original fashion in listening. 

THE WAY TO LUXEMBOURG 

It is interesting to note that having applied band- 
spread to higher frequency end of the Medium wave 
band to make it easier to tune in Luxembourg, other 
manufacturers are now doing the same thing— but no 
other set compares in size with the Micro-6. 

BRINGS IN PIRATES! 

We receive enthusiastic tellers from Mic£0-6 builders with such 
regularity (hat we could be forgiven for taking them as a matter 
of course. But a new note begins to appear in our correspondence. 
l.I-.C... Windsor, among many, reports excellent reception from 
Caroline and Atlanta anchored in the North Sea, whilst 
n is interesting to note that J.M., Bromley. Kent, listens nostalgi- 
cally to Athlone at the other end of the scale, ^T- 



380 




THE WORLD'S SMALLEST 



PRACTICAL WIRELESS August, 1964 

1 Itltero- 

\LLEST AND MOST EFFICIENT 




SINCLAIR MICRO-6 the world's smallest radio 



C17 r n, . „ ■«, » „ t- When you have built this wonderful set, you will find it your constant 
SIZE l*/« * '7tt X * companion everywhere-indoors and out-in _car, bus, tram-wherever 



COVERS M.W. BAND 

• 

WEIGHS LESS THAN 
I OUNCE COMPLETE 
with SELF-CONTAINED 
BATTERIES and AERIAL 



you want to listen. Its power it such that it ensures good reception 
under the severest operating conditions, yet it is so small you can wear 
vour Micro-* like a wrist-watchl Tuning covers the entire medium 
waveband with bandspread over the higher frequency end to ensure 
better separation of Luxembourg, Continental and other stations,. 
Listening is by means of the lightweight high quality earpiece provided 
(except when you want to use the set with the TR75C I and a loudspeaker . 
The earpiece switches on when plugging in, THE SET 15 so wtLL 
DESIGNED AND THE INSTRUCTIONS SO CLEAR THAT ANY- 
ONE CAN BUILD THE MICRO-6 AND HAVE IT WORKING IN A 
SINGLE EVENING. All part* including earpiece and instructions 

come to: 
Matlory Mercury Cell Type ZM.312 (2 required)— I 'I Id each. 



59/6 




SINCLAIR TR750 POWER AMPLIFIER 

MAKES A CAR RADIO OF YOUR MiCRO-6 

This outstandingly successful power amplifier builds on to a 
printed circuit board 2 x 2in. and includes Its own volume 
control with on-off switch. The TR.7S0 is primarily intended to 
provide powerful loudspeaker reproduction from the Sinclair 
Micro-6 or Slimline receivers, to enabli; owners of these sets to 
use them also for car radios, loudspeaker portables or domestic 
radios. Amongst many other useful applications, the TR75Q 
makes an excellent record reproducer used singly for mono or 
paired for stereo. Frequency response - IdB from 30 to 
20.000 t's. Transformerless output of 750 milliwatts for IQrnV 
input into 2 K ohms, using standard 25-35 ohm speakers. 
Operates from 9-12 volt supply. 



jtll paw i,k. MAT and 
.Watpuaain TrantlttDtl 
and instructions f«ne K> 



39/6 



Htady huiti 
for immediate 



45/- 



Supplied with plug for connecting to Miere-e ond Slimline. 



SINCLAIR RADIONICS LTD., 69 HISTON ROAD, CAMBRIDGE. Phone.- sws 



August 1964 



PRACTICAL WIRELESS 



381 



Masterpieces 

TRANSISTORISED CONSTRUCTIONAL DESIGNS 



A.6.C. 



-E 



Amp. 



1st R.F. _^ 2nd R.F. 



Amp. 



Detector 



MuT 



3 



A.F. 

Amp. 



2nd A.F. 
Amp. 



3rd A.F. 

Amp. 




6-STAGE POWER AND SELECTIVITY 

The Micro-6 uses Micro-Alloy Transistors in a completely 
new circuit as follows:— Two stages of R.F, amplification are 
followed by an efficient double-diode detector which drives 
a high-gam 3-itage A.F. amplifier. Powerful A.G.C. applied 
to the first R.F. stage ensures fade -free reception from the 
most distant stations 
tuned in. Everything 
including ferrite-rod 
aerial and batteries is 
contained within 
the elegant tiny 
case. 

CHASSIS 
SIZE ONLY 
1-2 x l.6Sin. 





Wear it 
a wrist 



like 

watch 



A rtrs •vnctmirni way (a um the J/icro-u. Simplp 
Mde the set on to the "Tranerista" wrist strap, 
fu rrtiffA it is sentrrl,/ hrltt h u means of the t pit ml 
mounting. The strap is tmll made in y i*j 

DUB ar areu nulnii — M twimt* i / 



nwitnnt.g, j ne strap (jt well 
Hack or QT£ ff Ttiflon and comU, 



Full service facilitie jjjvYjysjvjila ble to Sincla ir customers 



SINCLAIR INJECTOR MAKE A FM transmitter 



The Smallest 
and molt 
efficient 
of all 

■ l vr II 

MATS H feu- 

and in. 



signal Into any 
part i-r aqulp- 
lueni at any 
frequency 

from 1 ko/e to 
SI Mo/( i.i 
locate I'milia 
rapidly. 

l''i * !'/„ i 
tin. excluding 
probe. Full in- 
struction* with 
every injector 
make building 
and usiiiK uHny. 




EASy TO 
BUILD ' 
EAST TO BSE 

Parti and in- 
structions eanta 



Ready 
Built 



27/6 
32/6 



SMa Ih i.np o( Ih* things you ran ilo 
with tills fantastic Sinclair amitliflrr 
an tlBBL-rllmil In the instructions, it j B 
"iin&l. pi tee! Freiiiii'iicy 
response ;io lo 00,000 eh ildB 
power K ni„ owe (1,000,000 times)— 
also makes a imperii broadband K. K 
an.!dl!lt-r, ,» r „ *ubminlature hl.jl 
amplitn-r with an output mHnbk lor 
SfTi. "tP'''"'* ur ev ™ loudspeaker, 
with MAT transistors, inst- — 
ructions and all parte. 



28/6 



THIS VEST-POCKET RADIO IS 
EXTRA EASY TO BUILD 



The Sinclair Slimline is ideal for newcomer* 
to set building keen to get their hand In. It 
ha* self-contained ferrite rod acrls.1 nn d 
takes standard PPS battery, yet „,,«,,„* 
only V»l u i )ii; lt s jjn. -j^^ ovcr lh( , 
medium waveband. Great power and quality 
.Building la particularly easy. All parts 
tndiuilng roi/a! Hue and gold rase, Aft IC 
earplfM a Mi inniruotiont cdw (o *W / O 




SINCLAIR GOLDEN 
MAT TRANSISTORS 

Aj specified lor Hlnro-6, TR750, etc., eta. 
give estremely high power gains and greatly 
Improve pcrfiinunnec ol any B.F. or A.I'. 

circuit. 

HAT 100 High gals low level. . 7/0 

HAT 101 F.Ttra high gain, low level . " 8^8 

HAT 130 High (Bin, medium and high level 7/B 
MAT 131 Extra higb gain, medium and high 

level .. .. S/S 

ADT 140 For F.H., T.V., V.H.F. andV.H.F. IB/- 



s 

A 
transistor 

GfoQs. phenomenal per- 
formance. Maximum 
dissipation obtainable 
up to 30 watts! Oaln 
greater than 100 at 
1 amp and at least 
final to 100 at il amps. 
As used In TH7B0. 
Bettei than any other 
available. 



NCLAIR 'MAGNAGAIN' 
sensational new power 



18/- 



THE WORLD 5 SMALLEST 
BATTERIES 



Slalkiry ZMSV2 (or 
RM312) Mercury cell 
as used in Mioro-G. 
Every experimenter 
should use thetul Id 
packs of ali, Special 

MBr - 10/6 




3 IMPORTANT BOOKS 
FOR CONSTRUCTORS 

OENESAL 

"M Tested Circuits frJng Micro Alloy Tran- 5/8 

" lst " r '- I'oilfter. 

SHORT WAVES 

"Tested (Short Wave Receivers Using SI ATs." 5/8 

Post free 
B.W. & COMMTmiCATlOirS " 
Tested Supcrhet Circuits for Short Wave B/8 
and Communicatlou Receivers, uamg MAT*," 
All three ordereu tOKotner J8/8. Pattfret 



UNIQUE SINCLAIR 
GUARANTEE 

II no are not oompleteh; tatisfled with your nnr- 
ohaae (we are confldcat that you will be doUgbtedj 
your lull pnrchase prtoe will He islundad instantly 
and without question. 

if nan do not with to aa 0111 coupon below please 
mention P.W.S when ordering. 



, TO SINCLAIR RADIONICS LTD., 69 HISTON ROAD^AMBrTdg!"' 

|P/eose send items detailed below £ s d i ' CAMBRIDGE , 
| j NAME | 

I '■ I ADDRESS 

I 1 

■ ^ — —■ i 

I ■ I 



TOTAL L 



^Far vMeh / ^cfw, rash'eAeour !m tmr n order I BLOCK LETTERS 



P.W.8I 



382 



PRACTICAL WIRELESS CLASSIFIED ADVERTISEMENTS 



August 1964 



RECEIVERS & COMPONENTS | 

_ 

TRANSISTORS! Give-away price. 
NKT124/5 Power Type. 6 for 10.'-. 
2SOS7 -1W. up to 60rac/s. 5/- each. 
Post free. G. F. MTLWARD. 17 Peel 
dose, Drayton Bassett, Staffs. 

RESISTORS! You can't resist this! 
iW, 1W. 2W Polythene wrapped on 
cards of 10. Mixed values and watt- 
ages, £2 /to,'- per 1,000. Your selec- 
tion 10/- per 100. G P MILWARD, 17 
Peel Close. Drayton Bassett, Staffs. 

"HEATH KITS" can now be seen in 

London and purchased on easy 

terms. Free brochure. DIRECT TV 
REPLACEMENTS LTD., Dept. PW7 P 9. 
126 Hamilton Road, West Norwood. 
S.E.27. GIPsy Hill 6166, 



TUBES— FAMOUS MAKES! 

MW43/69. AW43/80, MW36/24, AW43/88 
etc. Fully screened, alurninised, 100% new 
(except glass). Mostly £4, 1 5s. (I2'6 cgc). 
LISTS, One Year's Guarantee Card. 
We do NOT sell regunned only tubes. Also 
NEW VALVES, 12 months guarantee! 
P. BE ARM AN, 43 Leicester Road, 
New Barnet, Herts. TeL: BAR 1934. 



SPE A ICE R REPA I RS, cones fitted. 
Satisfaction guaranteed. L. S. 
REPAIRS, Pluckley, Ashford, Kent. 

TRANSISTORS now naif price, 
unmarked but tested packets of 18, 
unmarked untested packets of 40; 
duds suitable as diodes, packets of 
80. All packets 10/- each, postage 
1/-. Four packets post free C.W.O. 
K. R. WHISTON (Dept PWT), New 
Mill*, Stockport. 



SPECIAL PURCHASE 

of 

"NOMBREX" 

TEST EQUIPMENT 

Signal Generators Model 27 

FULLY TRANSISTORISED 
Ranges 1 50 Kc/s to 350 Mc/s 
LIST PRICE £9.10.0, 

OUR PRICE £8.8.0 

C.R. Bridge Model 62 

FULLY TRANSISTORISED 

OUR PRICE £7.17.6 
Ranges: I ohm-IOKohms 
I00ohms-l Megohms 

IOKohms-100 „ 
LISTED PRICE £8,5.0 

Audio Generators 

FULLY TRANSISTORISED 

OUR PRICE £15.15.0 
Ranges 10-100,000 cycles in four 
multipliers. 

LISTED PRICE £16.15.0 
Further Particulars and Lists, 

Send S.A.E. to:— 

DIAMOND (Mailorder) PRODUCTS 

(Dept. PT) MBC/DIA 
LONDON, W.C.I 



L 



RATES! 7/3 |)t-r line or part 
tlit-rcof aVCTWW live words to Hue. 
minimum l lines. K»* V". 1/- J'* 1 ™- 
■Vdvei-li^cnii'iil'i must I"' prepaid and 
iidrtrei-ifd l» AU>citi>enii-iil 

Manager, "ITuitkaJ Wireless, 
Tower Mouse, Southampton St., 
London W.C.S. 



FOR SALE 



RECEIVERS & COMPONENTS 

(continued) 



A.I. POST FREE BARGAINS. Guaran- 
teed set tested valves. AF80. EB91, 
10F1 9d. each, 3 for 1,6. L36, ECL80 

2 - each. PY3I. FZ3Q. 3 -. PY80. PY82 

3 3. BCC81. ECC82. 3 6. PI -32 3.9, B36. 
PCF80 PL83, 20P1. 4-. EBF80, N3i. 
H3. FL33. 4/6. PUU. 4/9. 3QFS, $/-. 
53KU 6,6. 185BT 7/-. Send for full 
list of cheap valves. A... RADIO 
COMPONENTS, 14 Trie Borough, 
Canterbury, Kent, 



THE FINEST and cheapest mail-order 
service in Britain now supplies every- 
thing Electronic ElecLrical. S.A.i,. 
brings details of genuine barga.n 
offers. HANDLEY, 112 Baysham St.. 
Hereford. 



R & R RADIO & T V SERVICE 

DeDt. P.W. 
41 MARKET STREET, BACTTP 
Tcluplione 485 
SALVAGE VALVES Tested before dispatch. 

CF13 416 101*11 8/- PL88 3/8 2<B»4 W 

tiLLfl 4fl 20 PS e/6 U801 7/8 301-10 5/- 

Um 1 8 WW 7 - Un 1/6 PCC84 4 - 

HOCSS 3/- 6flS 5/- MPS 5 6 PCLS3 6/- 

HCLSOae EB91 II- 3FI.1 6- Iffl 8/8 

£E& 1 1- SM» 3 - « LICIT 5/- 10P1 6/8 
PCF80 4/- aol-a 8/- m f(8 gW» g- 
PJ-Si S - SOrLl 4/- »Oe*l 3/- 30J?13 5/- 
PZS0 5/- VLS6 8/- SS */- PT82 6/- 
D329 5/- PCLBU 6/- 

Speaier*. Ei-TV. Bin, round, 8 i 4in„ 3/8; Sin. 
round, 8/-; post 2/-. 

Line Output TranilormMi available. State net 
model No. 

Turret Tun«r9, 8/-, post 2/-. 

Scan Coils ete. Quote set mode] No. with all en- 
quiries aud B.A.E. lor uruiupt replj-. All goods 
aubjeei to satlarartlini or wonij- refunded. 



HAMMER FINISH PAINT- „ The 

modern finish :or al. electron-^ 
equipment. (.Not crackle flnisni. Jjsi 
brush it on, no moving, the effect 
appears at once and dries In 20 
minutes. Blue or pewter 21 02. Eras 3 6, 
i pint 7 6, 1 pint. 15;-. From radio 
& model shops or post free from us. 
Trade supplied. PINNIGAN SPECI- 
ALITY PAINTS, ipwi, o Stanley Sa.. 

Stalybrldge. Che s. 

SURPLUS SWITCHES. Capacitors 
Valves, Transistors. Transformers etc. 
New. very cheap, s.a.e. list. Rosedene. 
Evershoit, Bletcbley. 



MORSESSf ! 

The famous RHYTHM RECORDED 
COURSE cuts the practice lime down 
to an absolute minimum! 

One student, aged 20, took only 13 
DAYS and another, aged 71. took 6 
WEEKS to obtain a G.P.O- Pass 
certificate. If vou wish to read Morse 
easily and naturally enclose 6d. m 
Stamps please for full explanatory 

To G3CHS, 45 GREEN LANE, 
PURLEY, SURREY 



5-TON FACTORY CLEARANGE, 

Radio, TV Electrical Components, in 
mixed parcels. Example; 28! b. mixed 
parcel £1, PP &/-■ Speakers, grilles, 
valves, bases, i.f.s. covers, condensers 
etc. Hundred other items. S.A.E List 
and Postal Orders to P NEWTON, 
16 shalcross Crescent, Hatfield. Herts. 
SALE. Ex Ministry Ground Radar 
Unit, new and unused. Cost £2,000 
when built. Weight 5 cwt. Offers^ 
E, M. MARRINER. 27 Hurworth 
Rd., Croft. Darlington, 



DIRECT TV REPLACEMENTS LTD., 

largest stockists or TV Components 
in the UK. Line Output Trans- 
formers Frame Output Transformers. 
Deflector Coils for most makes. 
Official sole suppliers for many set 
makers. Same Day Dispatch Service. 
Terms C.O.D. or C.W.O. Send S.A.E. 
For quotes. Day and Night Telephone 
GIFsy Hiil (J166. 126 Hamilton Road. 
Wast Norwood, 8.E.27. 






TESTED TRANSISTORS 



I/- each, Red or White Spots. 

ZL each, XAI0I, XAI02. XBI03, 
XBI04, OA90, OC430. 

3'- each, OC44. OC45, OC70, 
OC71, OC8I, OC8ID, OC200, 
GETI6. 




POWER UNITS. For 200 2a0iolt AG 
mains Outputs. 2»0 yolts D.G. 100 
MA., 6.3 volts A.C., 4 amps Doub.e 
choke and paper •apaolto* smoothing. 
Fully fused. Siise 19in. rack panel x 
Tin x lOiin deep, complete with 
dWt cover. .Suitable for R1392, P104 
and R1132 receivers. In good con- 
dition. £2/5/-. Carriage .l«/-*J°M§ 
Two Metre Unit. Transceiver SCR522. 
100 to LSOmcs, crystal controlled (no 
crystals i. Receiver section valves, J 
of'"i2SG7. 12CC, 12AH7, 12J5, 3 Of 
9003, 9002. 12H6. Transmitter valves, 
6SS7, 3 of 12A6, 6G6. 2 of 832. Very 
useful moduiation and driver f?" 5- 
formers for push pull I2A6 (or 6V6). 
Price only 50/- wiLh all valves. No 
attachments. 



40/42 PORTLAND 
ROAD. WORTHING 



4'- each. AFIM, AFII5, AFII7, 
OCI70, OCI7I. 



5L each, OC72. OCI39NPN, 
OC800. OC204, ORP60. BYIOO. 

I0L each, OC35. OC26, GET57I . 

ZENER DIODES 4.7 v. to 33 
volt i watt, 3'6 each. 1 .5 watt, 
5'- each, 7 watt, 6f- each. 

Send 3d. stamp for Full 
Price List, and Free Equiva- 
lent Chart. 

B.W.CURSONS 

78 BROAD STREET 
CANTERBURY, KENT 



: 



August, 1964 



PRACTICAL WIRELESS CLASSIFIED ADVERTISEMENTS 



383 



SUPER BREAKDOWN UNIT 

Remote Control Unit Type F. New in 
sealed cartons, containing P.O. Relay 2,000 
ohms Resistance, 100 volt Ptessey Hand 
Generator, Telephone Ringing Bell A.C. 
8 amp Morse Key on base, 2 D.P, D.T. 
Key Switches, Double Phone Jack, moulded, 
5 position 6 pole Yaxley Switch, Induction 
Coil tapped 1-17-33 ohms. 7 Brass Screw 
Terminals on panels, plus Resistors, Con- 
densers. Pointer Knobs. All in a handy 
metal box with hinged: lid and side fasteners. 
Also web carry strap. Siie 10,-in. x lOin. x 
7in,, 25'-, post free. Or items may be 
purchased separately. Relay 5'-, Hand 
Generator 7'6, Beit S'-, Morse Key 4'6, 
Key Switches 5'- pair, Double Phone Jack 
2'«, Yaxley Switch 2'-, Ind Coil 2'-, Termi- 
nals 7 for 1'-, all post free. 



FOR SALE 

( continued i 



Also available Key Switches. 4 pole 
2 throw 3'6 each or 3 position D.P. 
plus D.P. centre off 5'- or rotary switch 
6 pole 3 way 3'-. 



Bank of 4 Pye Sockets with plugs and leads 
5'- set. Ever Ready Batteries, 90 volts plus 
4i voltr 4 '4 each. 
Pfessey 2-4- 1 2-25 way plugs and sockets, 

all S'. pair. 

Jones Plugs and Sockets 4- 1 2- 18-24-32 way 
■II 5'- pair. 

Special Lightweight 7in. x 4in., 3 ohm P.M. 
Speaker, 6'-. 

Metal Frames, suitable for stock, Job Cards, 
Bins, Crates, 2^in. x Sin., I2'6 per 100 — 
£4 per 1,000. 



IMn. RACK FITTING CABINET' 

34' high by 21* deep with telescopic 
drawer slides. Louvred aides, back and 
top. Brand new Swedish make, £4.0.0 
only, pi as B.H.S. delivery. 



!£§„ Tube ^ th Screen and Base with 
f»CB 35 data, 251'. 

5UP7 Tube with Screen and Base, with 
data, 30/-, 

20ft. Steel Telescopic Mast. SO/-. 



ELECTRICAL 
CAMERA CONTROL 

This item is brand new in 
varnished wood case original 
packing. Makes a good timer 
for exposure. Infinitely variable 
up to one minute. 24 volt 
operation. Containing motor, 
solenoid, clockwork mechanism. 
Driven by motor. 30 f. post free. 



Copper Laminate Board, single or double 
sided. 5/- per square loot panels, either 
type 3ft. by 4ft.. 38/-. 

Hteh Stab Resistors. 5% 6d., 2% ga„ 

1% V-. Every six packed in 7-eomparcment 
linen finish component box. Unmarked. 



Speakers. 3 ohm P.M. Bin. 5/-, 6in. 6/-. 
7 s 4in. 7K Sin. 8/-, Win. J.s/6. 



E. R. NICHOLLS 

Mail Order and lliiull shop: 

« LOWF1ELD HO AD 

off SHAW HEATH. STOCKPORT 

t in sium 



240 'ELECTRIC POWERflZEW 



— from 12 '■■■ Car Battery 

TsiS^^WMAMOTOR UNIT 

111! 1 1 It. Ml HI lm, 7Ml II (SI !( tM n m 

ftiiiti lu mivitiH. re*u loon iii ii 

Mi i«jl »C K i 1 [ ( HI ( 1U011 1 MCHT Jl <« 
RlllfllJ IHiiKI Mil a«lT/B . ri ■ nrr l|< 
M :'.--!lni i ::: V ': .:• in li'uli 
W KtisliiitrjoaucTi cuvuirs.uttt 




CONDENSER BARGAIN! Miniature 

paper condensers, jin. x tin, Ideal lor 
transistor se^. .0001, .001. .0O2, .005 
.02, .04.if. Your choice. 7/Bd. per 100 
or £3 psr 1,000. G. F. MILWARD, 17 
Peel Close, Drayton Bassett. Staffs. 

ALBATROSS ENG., CO. 

NEW COKPOHEKTB ft TOOL BARGAINS 
IS Resistors * 18 Spring * fi Knobe * 12 Clamps 
t! T» K strips • 5 Valve Holders ■ 7 Coll Forme™ 
30ft. Steevlng * 170 sq.in, Rexlnc * 20ft. Prcstlc Com- 
pound • 3fi Self Tap Screws ■ 100 aieevet »nd Gram- 
met* • 2S0 hi Jn. Almn, Screen * 100 sq.ln. Insulmtlng 
Card " 24 eq.in. Felt T»p« * 12 L/9 Gauzes • 20 
Mounted Tags • lit ea. (P. * P. (Id.) or Lot 17/6 <3'3> 
ij Ceramic Condensers • Ss Condenser Clips, etc. 
1« Socket Panels • li Colla • 3 PoU * 8 RF Choke. 
3 2 a. 3 p. sw Sockets * B wafer bv., addons * billets, 
fi Trimniers * Gram moontlni! Kll • f wave rectifier 
Twin Ion Trap » 10 SE« Tjunpholders ' 3 Impedance 
Matching Panels * 4 Printed ects * 19 Anti -vibration 
Mounts • 2/8 each (1/- P. & P.) or Lot 87/8 (316). 
'I Maine Droppers ■ 16 Sub-mln. A Stamp Trimmers 
8 Electroiytles * 7 Block Papers * IS Melalparkg 
SO Mica Conds. • 40 Ceramic ■ 24 Eqnit Feet 
3 Slider Switches ■ ISO Felt Washers • 20 Fn« 
Holders etc. » 12 Bolbe • 10 HD Carbon Brushes 
40 docket Panels " St- each pack (plus 1:3 P. * P.). 
EX GOVERNMENT EQUIPMENT rMint Condition) 
Pocket Voltmeters fl-LviJ.MOv. 9/B (l-fl). 4 Valve 
Modulators U/6 (2,'S|. ACD3 TV PCs. 11/- (1 fS). 
Ao, 19 Twin Control Units, 0/- (2/3>. 7 Ken- TV Pot* 
on Strip 7/6 <1». Dimmer Swllcbes, 7/6 (94.). 
Modulator Unit No. 2, (18. Modulator Unit No. 28, 
til. Pulse Generator No. 19, £8. Test Set Mlc. Jt 
Receiver No. 4, til. New Had to Chassis, 7/6 (2'fii. 
Ditto Larger, JJ/8 (SI-). 0-40 R.P.M, Meters, 84/- 
(2/0. Voltmeter (Webbing) Cases, 1/6 (8d.(. Large 
Fore. Insulators Overhead 8/8 pair (l/-i, SV 8P 
Vibrators, 6/8 (IH. 

Bargain Parcels:— Onr seketlon^of New Misc. 
components (ncladlcg abore types; lib.— 4/-, 21b. •= 

7/-. ait... lo/-. 4ib.-u/6, f»ib.=i4/e. oib.-ie/-. 

WI..-18/3, 101b. -B0/-. iPlt M p. & p.j. 

Radar Equipment to caller* — Catalogue 1/ come 

and have a look round. 

foetal— 4 In 1 Screwdriyer Bet, 6/11. 2 Flei-shalt 
Screwdrivers, 8/11. a-way ?hi]lpr Screwdrivers, 6/6. 
.In. Pliers, 3/6. tarolated PBtnx, 7/6. Wire Stripper 
4 Cutler, 2/6. 11 piece Socket wet. 9/8. 7 piece Nut- 
P river flet, 8/11. Knbtwr Hammer. 1*/-, Panel 
Reatiiit; Hammers. 12/11. Small, 8/11, 9ln. Hack- 
saw Blade*. 44. Fini»lilnK Trowels, 10/6 A 12/8. 
Oroovlng Trowel, 8/11. Pointing Trowel. Sim, t/6. 
I U I \i.-J P. 8 P. on all Ordera under £1.) 

ALBATROSS 
ENGINEERING COMPANY 

Dept. P.W.4S 78-80 HIOH STREET, GOSBERTGN 
SPALDING, LIBOS. Tel. Goiberton 468 



WANTED 



A PROMPT CASH OFFER for your 
surplus brand new Valves and 
Transistors. R.H.8., Beverley House. 
Mannville Terrace. Bradford 7. 



WANTED 
VALVES ONLY 

Must be new and boxed 
Payment by return. 

WILLIAM CARVIS LTD. 
103 North Street, Leeds 7 



WANTED 

(continued) 



WE BUY new valves for cash, large 
or small quantities, old tvpes or tSe 
latest. Send details, Quotations bv 
return. WALTONS WIRELESS 

STORES. 15, Church Si.. Wolver- 
hampton. 



WE BUY new Valves and Transistors 
Amplifiers. Short-wave Receivers and 
Components, etc. A.D.A. MANUFAC- 
TURING CO., na Alireton Road, 
Nottingham. 



NEW VALVES WANTED 

Any type, or quantity 

CASH PAID 

R.S.T. Valve Mall Order Co. 

21 IA Streatham Road 

Mitcham, Surrey 

Telephone; MITCHAM 6202 



MISCELLANEOUS 



YOUR KITS expertly built. Mains Se 
Battery Radios, etc. of every descrip- 
tion. Enquiries — S.A.E. to JOHN 
THOMAS, 106 North Avenue, RuaJjon, 
near Wrexham. 

CONVERT ANV TV SET into an 
oscilloscope. Instructions and dia- 
grams 12 /». REDMOND, 2fl St John\H 
Road, Hove. Sussex. 

|— ELECTRONIC MUSIC?— 

Then how about making 1 yourself an 
electric onran? Constructional data 
available-^ull circuits, drawing's and 
notes! It baa 5 octaves, S nnwn ia and 
pedals with 24 stops—uses 41 valves, 
with its variable attack you can play 
Classics and Swing. 

Write N'OW for free leaflet and further 
details to C. A S.. SO Maude Street, 
1 >ur n ugion, Durham. Send 2?d. stamp. 



LAMINATED PLASTIC engraved 
nameplates for your P.W. Guitar 
Amplifier Control Panel. 15<'6 Post 
Paid. Engravings to your specific <i- 
tion. Enquiries S.A.E. HOLDEN, 20 
Maesgwyn, Cwmbran, Monmouthshire 



ALUMINIUM 

Sheet for Radio Chassis and general 
use. Cut to size. Also Brass, Copper, 
Steel, etc. in Sheets, Tubes, Rods, 
Foils, Sections, etc. Write for FREE 
ILLUSTRATED FKU fc LIST. Cal- 
lers welcome. 

SESMOR METALS, Dept. R/« 
35 St. Johns Road, Iwleworth. Middx. 

ISU: 6017 



SOUND RECORDING 



A UNIQUE BUY! Recording Tape, 
top brand. 51in. 1,300ft., 18/6; 7in , 
2.4D0rt.. D.P.. 28/«. P. and P. l/« per 

spool. Bargains in all eizes. SA.E 
for list. E C. KJNGSLET AND CO., 
132 Tottenham Court Road. London. 
W. 1. EUSton 6500. 



384 PRACTICAL WIRELESS CLASSIFIED ADVERTISEMENTS 

SERVICE SHEETS EDUCATIONAL SITUA 



■ 



SERVICE SHEETS for all makes of 
R;ldio and TV. 1925-1964. Prices from 
i - with free fault-finding guide, 
S.A.E. inquiries. Catalogue of 6.500 
models, 1/6, Valves, modern and 
obsolete. Radio/TV Books. S.A.E. 
JLsiS. HAMILTON RADIO, Western 
Road. St. Leonards. Sussex. 



SERVICE SHEETS, Radio and Tele- 
vision, 3/6, post paid. VEST AND 
EMERY, 17 HaHgartii St.. Durham. 

SERVICE SHEETS: Radio. TV. 5,000 
models. List 1/-. S.A.E. inquiries. 
TELRAY, 11 Maudland Bank. Preston. 

SERVICE SHEETS: Radio and TV 
4'- each, 1964 list now availab.e. 1/6. 
All orders dispatched on day received 
Also Manuals for sale and hire. Lis! 
1/-. S.A.E. please. SULTAN RADIO. 
39 Church Road, Tunbridge Wells, 
Kent. 

S.E.S. SERVICE SHEETS Jor all TV, 
Radio and Tape Recorders, etc. List 
1/6 plus S.A.E. SUN ELECTRICAL 
SERVICES. 38 St. George's Road, 
Hastings, Sussex. - 

RADIO SERVICE SHEETS, 3/ 6each. 
S.A.E. and P.O. to HANDLEY, 
Bastian Mews, Hereford. 



WANTED — Service Sheets and 
Manuals. No quantity too large, high- 
est prices paid. SULTAN RADIO,- 29 
Church Road, Tunbridge Wells, Kent. 

SERVICE SHEETS, also current and 
obsolete Valves for sale, JOHN 
GILBERT TELEVISION, lb Shep- 
herd's Bush Road, London, W.12. 
Phone: SHE 8441. 



SERVICE SHEETS 

4'- ea., plus postage. 
We have the largest display of Ser- 
vice Sheets for all makes and types 
of Radios, Televisions, Tape Recor- 
ders, etc., in the country, and can 
supply by return of post. 
To obtain the Service Sheet you 
require, please complete the at- 
tached coupon: 
From : 

Name: — — 

Address: — 



RADIO OFFICERS see the world. 
Seagoing and shore appointments. 
Our manv recent successes provide 
additional trainee vacancies during 
1964 65. Day and Boarding Students, 
Grants and scholarships available. 
Stamp for Prospectus. WIRELESS 
COLLEGE, Colwyn Bay. 



BECOME "TECHNICALLY QUALI- 
FIED " in your spare time. Guaran- 
teed Diploma and Exam. Home-stufly 
Courses in Radio. TV Servicing and 
Maintenance. R.T.E.B.. City and 
Guilds, etc. His lily informative 120- 
pa«e Guide— FREE. CHAMBERS 
COLLEGE (Dept. 363), 148 Hotborn, 
London. E.C.l. 



TRAIN TOR SUCCESS: 
WITH ICS 



Study at home for a progressive 
post in Radio, TV and Electro- 
nics. Expert tuition for I.E.R.E., 
City & Guilds (Telecoms and 
Radio Amateurs'), R.T.E.B., 
etc. Many unique diploma 
courses incl. Colour TV, Elec- 
tronics, Telemetry & Com- 
puters. Also self-build kit 
courses — valve and transistor. 

Write /or FREE prospectus and find out 
how ICS can help vou in your career 
ICS DEPT. 541, PARKCATE ROAD, 
LONDON, S.W.I I. 

u 



(continued.) 



To: S.P. DISTRIBUTORS 
44 Old Bond St., London, W.I 

Please supply Service Sheets for the 

following i 

Make: 



Model No. 
Make: 



Radio/TV 



Model No. 
Make: 



Radio/TV 



Model No. 



Radio /TV 



I also require list of Service Sheets 

at 1/6. 
I also require list of Manuals at I P-. 

(please delete items not applicable) 

I enclose remittance of- 



I.E.R.E. CITV AHD GUILDS and 

R.T.E.B. exams. Specialised I.C.S. 
home-study course will ensure 
success. For details ot wide range ■ of 
exam, and diploma courses in Radio, 
TV and Electronics, also new P^ctv- 
ca' courses with Kits, write to I.C.S, 
iDept. 542), Farkgate Road. London. 
S.W.ll. 



RADIO AND TV exams and Courses 
by Britain's fines: Hams-study Schoo.. 
Coaching for Brit.I.R.E.. City and 
Guilds, Amateur's Licence, R.T.L.B.. 
P M G Cert etc. FREE brochure 
from 'BRITISH NATIONAL RADIO 
SCHOOL. Russell Street, Reading. 



J 



A.M.l.Mech.E., A. M.I. Brit.I.R.E., pity 
and Guilds, G.C.E., etc., brings hijrh 
pay and security. "No pass— no pay 
terms. Ovftf 95% successes. For 
details of exams and courses -nau 
branches of Engineering, BUhdmg. 
Electronics, etc., write for 14H-P<*je 
handbook — free. B.I.E.T (Dent. 
242B). 29 Wright's Lane, London, W.tJ. 



TECHNICIAN required for Interesting 
post of technical storemaa. The per- 
son appointed will be given ^ne 
opportunity to assist in the design, 
construction and servicing of elec- 
tronic and mechanical apparatus. 
Applicants should have a working 
knowledge of general workshop prac- 
tice, toe capable of neat work and 
would be expected to help in saying 
out apparatus for laboratory classes. 
Application forms from Secretary, 
University College. London, Gower 
Street. W.C.I, quoting Psycho/1. 



THE INCORPORATED PRACTI- 
TIONERS in Radio and Electronics 
(IP RE Ltd.t. Membership Condi- 
tion booklet 1/-. Sample copy of 
I P R E. Official Journal 2/- post free. 
Dept. B Secretary, 32 Kidmore Road, 
Caversham, Reading. Berto. 



BOOKS & PUBLICATIONS 



FIND TV SET TROUBLES IN 
MINUTES from the great book. The 
Principles of TV Receiver Servicing, 
10 '6 all toook houses and radio whole- 
salers if not in stock irom Dept. a 
Secretary. 32 Kidmore Road, Caver- 
sham. Reading. Berks. 



SITUATIONS VACANT 



MAIL ORDERS ONLY 



TV AND RADIO, A.M.I. Brit.I.R.E., 
City and Guilds, R.T.E.B. Cert., etc.. 
on "no pass— no fee" terms. Over 
95<?i successes. For details of exams 
and courses (including practical 
apparatus) in all branches of Radio. 
TV and Electronics, write for 1413- 
page handbook— free. B.I.E.T. iDept. 
242G), 29 Wright's Lane, London, W.8. 



ARE YOU INTERESTED IN 
INSTRUMENTS O.'t ELECTRONICS 

and their 

APPLICATION TO AIRCRAFT? 

The College of Aeronautics offers an 
opportunity for an enthusiastic young 
man to learn new techniques in flight test 
instrumentation. Tidiness, ability to handle 
delicate instruments and attention to 
detail are essential. The successful applicant 
will, after a probationary period of training, 
take charge of a small laboratory and be 
responsible for calibration and installation 
of flight test instruments in the College air- 

The post is established in a skilled grade 
in accordance with the N.J.C. scales for 
Civil Aviation. 

Applications, giving full particulars, to 
CHIEF CLERK 
The College of Aeronautics, 
Cran field, Bletchley, Bucks. 



METAL WORK 



ENGINEERS REQUIRED 

Experienced in audio techniques and 

relay circuitry, for work on public 

address systems. 

Write, giving details to: 

CLARKE & SMITH MFG. CO. LTD.. 

Special Products Division, 

Hanworth Air Park. 

Feltham. Middlesex. 



METAL WORK. All types cabinets, 
chassis, racks, etc., to your spf crea- 
tions. PHTLPOTTS METAL WORKS 
LTD., Chapman St., LougnbOTOUgb. 



CABINETS • CASES 
CHASSIS 

Anything in metal. "One-offs" a pleasure. 

Send your drawing for quote 
Stove enamelled in any professional finish 

MOSS, WATSON 

«Mou«t P.--* Street, ffdh.m. 



PRACTICAL WIRELESS 



385 

COMPLETE FAMILY 

LAWYER 

»»m#MHS!4* mill — 1i . 




I IN BUSINESS 

PATENTS • COPYRIGHT • TRADE UNIONS 
EKPLOYMENT - SALE OF GOODS 
PARTNERSHIP • STARTING A BUSINESS 
INSURANCE - INVESTMENT ■ TAX 

CONTRACTS • BANKRUPTCY gi"i"«iiiW"Hi! 

= EDITEO 



► IN PERSONAL AFFAIRS 

BUYING AND SELLING • LEASES 
ACCIDENTS ■ MARRIAGE ■ SEPAR- 
ATION, DIVORCE ■ SUNDER - HP 
AND CREDIT SALE ■ NEIGHBOURS 
WILLS • FREE LEGAL AID 



= a r 




Dudley 
Perkins 

Known to millions for ... 
popular BBC broadcasts on 
legal matters 



STUDY IT FREE FOR 7 DAYS 



Written in Everyday Language by 
leading Barristers and Solicitors 

Everything in Law— Land ownership. Leases. 
Tenancy Agreements. Repairs. Sub-leuing. Rem- 
control. Parents and Children. Changing your 
name. Negligence. Blackmail. Misrepresent li.n. 
Pensions, lOUs. Libel. Slander. Damages. Town 
and Country Planning. Provocation. Trespass. 
Nuisance from noise. Factories Act. Cheques. 
Road Traffic Laws. Rights of a finder. Neigh- 
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Law on Clubs, Gaming, Lotteries, fishing Laws. 
FREE LEGAL AID explained . . . And much 
more besides. 

HANDSOME DURABLE BINDING 
WITH CONTEMPORARY DESIGN 

^n n r 1 1 1 j 1 1 r i f j r n 1 1 n r j r i h 1 1 1 r i r 1 1 1 n m i ' ii i f i ' 1 1 1 u n i n i ■ 1 1 1 1 1 (i= 

THIS IS THE FIRST 

ILLUSTRATED FAMILY LAWYER 

= DUDLEY PERKINS clarifies points of ^ 

^ law with ISO special illustrations— the = 

: modern way to explain simply! Send = 

; now and see this practical new Home = 

= Lawyer for a week without cost. S 

-~'i i.M.iiimii iii.Thirn.i u in iimnim miuihi 



In this complex age of do's and don'ts, rules and regulations, laws 
and liabilities, the need for an understanding borne legal guide is 
urgent. You know that ignorance of the law is no excuse— yet you 
are burdened by complicated language which only a legal mind can 
lalnom! Here at last is the answer— Newies FAMILY LAWYER 
which explains your rights and privileges and Uahihties in' all your 
personal, family and business affairs. It will save vou annoyance 
and anxiety ... and prevent you from taking risks. Study it free 
tor a week without obligation to buy! 



Past Fa-day 



r Q: GEORGE NEWNES LTD., IS-17 LONG ACRE, LONDON W C 2' 

chfsf S r*m N J;y N ' ES F ^ 1ILY LA ^ER without obhgation to'pur- 
fhf ." ui urn " ,n 8 days or send s '" deposit K da^ ailer delivery 

then ten monthly payments of 10'-. paying 105/- in all. AltcrnaiiveK ?n 
S days I will remit the full cash price of 105;-. Alternatively, in 

/' you are tinder 21 you" tathet must fill up coupon 
II married woman your husband must fill up. 



Full name _ ... 

f BLOCK LE1TFRS) 

Address 



A-/', 
< Mrs. 
I Mis* 



Tick <t where i 

TheiddfM5«lffl]i — 



Occupation. 



Signature 

(Mr.. Mrs., Miss) 



(FL)39 7I7 



HjPrHMr 




Mite. Mtonijlej 




PltMts' Home 


■- 


FurolslKd ktwu. 
^Ttitiporiry AmSrais 


- 



386 



TRANSISTORS 



AC107 


14/8 


AD140 


357- 


AF102 


27/6 


AF1U 


11/- 


AF115 


10/6 


AP11B 


10/- 


AF117 


9/6 


AF118 


80/- 


AF124 


10/- 


A.F125 


10/6 


AF126 


10/- 



AF127 


fi/e 


OAZ207 


7J- 


0C16W 


ftfl/- 


0C19 


BJf- 


0C2S 


Sih/- 


0Ci5 


!». 


OC42 


«,'- 


OC44 


B- 


OC44M 


»/» 


OC45 


M- 


OC45M 


»/- 


OCTO 


Wt) 


ucv I 


4/a 



OC72 


5/6 


20C72 


ltf/- 


OC74 


M- 


OC7o 


fVtt 


OC73 


&. 


OC81 


5/« 


OC81M 


a/- 


OC82 


10/- 


OCB3 


4/- 


OC139 


6f- 


OC170 


9/ 6 


OC171 


10/6 


GEX34 


4f- 


GEX35 


4/- 


GEX36 


10/- 



DIODES 

BY100 7/6 I OAflO 3f- 

OC70 3/- i OAai 57- 

OC79 3/- OA95 3/6 

0C81 2/- OA210 9/6 

SETS OP TRANSISTORS 
Set 1. Comprising OC44. 2xOC45, 

OC81 Driver, matched paix OC81 30/- sec 
Set 2. Coir.prising OC81 Driver. 

matched pair OC81 ., .. 10/- set 



PRACTICAL WIRELESS 



M ULTI-R AW 1 •". TfcSTU KTERS 



August, 1964 



Caby Ml .. 

Caby B20 
Eagle EPiok 

Model LiOOH 
Eagle EP50K 
COTS A10 
Taylor ista 
Eagle TK20A 
Eagle EP30K 



£2 14 
£6 10 
£4 12 6 
£5 6 
£9 19 6 
£4 17 6 
£10 
£2 9 6 
£6 19 6 



MICROPHONICS 



DK96 
DAF6 
DF96 
DLOS 

ECCSi 
v,€C32 

ECC83 

y.cca 

ECCS-5 

ECH81 

EBC41 

EF41 

EOU80 

PCF80 

K3/2S 
K3/40 

C3D 



7/9 

6/9 
6/9 
6/9 
5/- 
5/6 
6/- 
7/6 
7/6 
7/6 
7/8 
7/6 
7/6 
7/6 



VALVES 

PCC84 7/6 PCL82 
PLB2 7/6 6V6G 
PY83 7/8 GK7G 
UABC80 7/6 6AM6 
UAF42 7/6 EB91 
UBF80 7/6 IBS 
DCH42 7/6 IT4 
UL41 7/6 1S5 
EYS1 *" 8/- 3S4 
PL81 8/6 6K8G 
PL36 9/6 6L6G 
PCLB3 9/6 6Q7G 
PCF82 9/6 6X5G 
MFTAL RECTIFIERS 
6/9 I KB/25 6/9 I M3 
9/- I K8/10 9/- I R3/20 
Contact Cooled Types 
8/6 C3B 14/- C3D 
Silicon Rectifiers 
T?fiT. 500mA 5/- saoy, 500mA 

MlCROA-MMETER-S 

* MII.l.lAHMIlTi-RS 

0-60 uA. 39/6. 0-500 pA, 32/6. 0-1 mA, S7/6, 
0-6 1&A787/6. 0-300 v., 27/6. "S" Meter. 35/-. 



£1 12 fi 
12 6 
19 6 
12 6 

81 19 6 

7 6 
19 6 

£2 5 
£2 19 6 

8 

American Recording: Tape, standard 
plav oln. spool, 600ft, , «/6: 51in. spool, 
&50ft„ llf9: Tin. spool. 120Ort.. 14/9: long 
plav Sin. spool, 900 rt,. lg/6: 51 in, spool. 
1200ft., 15/-: Tin. spool. IBOOft,, 19/6. 



ACOS Mic 39/1 

Floor Stand Adaptor 

Acos Mic 45 

Table Stand 

Mir iOOC 

Table Stand 

Acos Mic 40 

BM3 Microphone 

Floor Stands MS4— 3 sections 

Table Top Stand 



9/- 
4/- 
2/- 
3/6 
3/- 
5/3 
3/6 
4/6 
5/6 
4/9 
7/6 
5/6 
51- 



19S4 CATALOGUE 56 PAGES 
.Now available send I/- in stamps for 
your copy. Trade Catalogue also avail- 
able. Please attach your Business 

Letter Heading. 

CATALOGUE SENT FREE WITH 
EVERT ORDER RECEIVED. 



GRAMOPHONE LMTS 

BSB TU12 unit, with Mono TC8H cartridge, 

£3 16 6 
BSR GUI unit, with TC8M or TC8H 

partridge. Mono, £4.15.0. 
BSR GET unit, with TC8S cartridge, 

Stereo. £5.5.0. . . „_„ 

Garrard Autosllm. automatic, with GC8 

Mono cartridge. £7,15.0. „,.„. 

Garrard Auioslim. automatic, with EV28 

Stereo cartridge. £8.10-0. ^ 

Garrard Autosllm. de luxe, with GC8 Mono 

cai ti idge, £11.5.0. 
Garrard Autoslim de luxe, with EV38 Stereo 

cartridge, £12.0.0. „„„ ,, 

BSB Monarch UAH. with TC8 Mono 

cartridge, £6,8.0. 
BSR Monarch UAH, with TC8S Stereo 

cartridge. £7.7.0. ,, 

BSR Monarch UA1S, with TC8 Mono 

cartridge. £6.19.6. m „ „ 

BSR Monarch UA16, with TC8S Stereo 
I cartridge, £7.19.6. 



IS watt Transistor Amplifier. 2 mixing 
and separately controlled inputs for micro- 
phone and gram, push-pull output operated 
from 12 v. battery, output 15 watts peak 
into 15 ohms low, size 9 x 61- x 6 Jin., weight 
61 lbs., price, £16.10.0. 

1 watt Transistor Amplifier, isolated 3 
ohm speaker output, 5 good quality trans- 
formers, nylon bobbins, pre-set volume 
control, living leads for 9 v. D.C. supply. 

2 Input points, with sensitivities of 10 mv and 
250 mv, size 31 x 2i X Uln„ weight 7 ozs.. 
price 43/-. 



ALPHA 

RADIO SUPPLY CO, 

! *" 5^ Z l03 LEEDS TERRACE 
WINTQUN STREET 
LEEDS 7 




TERMS; Cash wiln Order or t.O.D, 
I'ostajcc and Parking Charges extra. 
Single valves lid., Minimum Parcel 
Post charges ■>!.. Please include 
sufficient posing? with your order. 
Minimum C.O.O. fees and postage 
HfB. These Pnsiul Rates apply to 
U.K. only. For full terms or rius[nc*s 
see inside cover «f catalogue. 
Personal shoppers 9 a.m. to 3 p.m. 
Mon. to Friday, Saturday 10 a.m. 
in I P.m. 




7he?tM€H .. 

yew niea,/ 



HOLE PUNCHES 
InctantType 
1* diameter 

Screw-up Type 

"" diameter To«le switch ... 



I 

r 

44* 

r 



B7G 

BBA, B9A. 



diameter int. Octal . 



r 

I 



B9G 



£'10 ea. 

8' 6 ., 

8'6 „ 

9'- „ 

9'6 ., 

I0'2 . 

10 '8 .. 

1 1 8 „ 
13'4 „ 
162 .. 
IS'IO „ 
27'8 „ 
24' 4 „ 
33'2 „ 



Metor 
Complete Set £9.3.6. 
Me extra charge (or postage and pocking 
in the U.K. 

Oliver & Randall Ltd 

Dept, 7 

7 KELSEY PARK ROAD 

BECKENHAM, KENT 

TW j S^Jtnham 8262 



PHILIPS PAPERBACKS 

ON 

RADIO SERVICING 

AUDIO QUALITY, by G. Slot. 
I0'6. Postage 9d. 

AERIALS. TV, FM AERIALS, by 

D, Sjobbema. 10'S. Postage 9d, 

RADIO VALVES by E. J. Black. 
I0'6. Postage 9d. 

THE TAPE RECORDER, by C. G. 
Niisen. 13'6. Postage 9d. 

ALTERNATING CURRENT & 
ACOUSTICS, by E. J. Black. I0'4. 
Postage 9d. 

A.F. AMPLIFICATION by E. », 

Black. IQ'6. Postage 9d. 

GUIDE TO BROADCASTING 
STATIONS 
Compiled by "WW". Revised edition 
covering European long and medium 
wave broadcasting stations and all 
short wave stations of the world. 
5'-. Postage 8d. 
COMPLETE CATALOGUE I '-. 

THE MODERN BOOK CO. 

BRITAIN'S LARGEST STOCKISTS 
or British and American Technical Books 

19-21 PRAED STREET 
LONDON, W.2 

Phone; PADdingxon 4 1 85 
Open 6 doj^s 9-6 p.m. 



FIRST-CLASS -RADIO 
AND T/V COURSES'... 

GET A CERTIFICATE! 



After brief, intensely interesting study 
— undertaken at home in your spare 
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of Radio and T.V. Let us show you how. 

FREE GUIDE . 

The New Free Guide contains 120 
pages of information of the greatest 
importance to both the amateur and 
the man employed in the radio 
industry. Chambers College pro- 
vides first rate postal courses for 
Radio Amateurs' Exam., R.T.E.B. 
Servicing Cert., C. & C. Te'ecoms.. 
Grad. Brit. I.R.I. Guide also gives 
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FOUNDED 1885— OVER 

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CHAMBERS COLLEGE 

(Incorp. National Inst, of Engineering) 
(Dept. 461), 148 HOLBORN 
LONDON, E.C.I 



August, 1964 



PRACTICAL WIRELESS 




a, 000 OHMS PER VOLT 20,000 OHMS PEit VOLT 
MODEL TP-10. Beads AC MODEL TV-6S. R.aJs toJ- 
unj Ij.c. l-ulie tip t.j l.niiir i;ibcs ii]] in 1,000 D.O. at 
IU'. t-urrem toBOOmA; lto- 20,008 ohni pur von uini 
•Utanre to i M ". at lo.ono o.p.v,; d.C. 

tanretuliil"; Dci'lbtL. from;curreM vo liuUuiA; Keai=- 
—20 to -hSi>; Output jack; lance to JO Hegt.: Capaci- 
tor Audio mca»urutiieiit8, tance to O.OllK- Decibels 
Size: 3i*5xl|la. jtrom -'JO to + So. Size- 

t3.l9.ft, 3$x6}xl»lii. tSlBe' 



DOUBLE BEAM 

OSCILLOSCOPE TUBES 
Another purchaser of Type fJV 
15911, equivalent to Coesor 
09D as used In Oecllloacopee 
by Cobsot (330 «erie«> and 
Hartley £ Krskine (IS aerlee) 
Luted £12. 

ilmnd new in Make r' jig r I 
crates tCarriai.» a.'-i.***/ 



80,000 OHMS PER VOLT 
MODEL 600, Kcaila voltage! up 
to 1,£HXI D.C. at 30 000 oluna per 
volt and A.C. at 15,000 o.p.v.; 
D.C. current to 12 amps. Reds- 
j-ance to flO Megs.; Decibeta 
from —20 to -f fifl; incorporate* 
Internal bmzer fgr audible 
warning of direct shorts and 
Mocking condenser for A.F. 
output measurements. Size 
O'/is * 2!in. HUB.fl. 



HU. 



HIGH IBEQDENCY A.C. 
VOLTMETER. A First Orade 
Moving Iron Instrument with 
Gin. Mirror Beale, reading np 
to 180 v. A.C. at 400 and 
1,200-2,400 cycles. In sub- 
atautlal Oak casfi with 
removable lid overall size 
8( x 8{ x 9}tn. Made (or tht 
Air Ministry by Everett 
Edgcumb, and m jierteel 
order. Brand New and Un- 
mwd. OXXY £S. Can a bo be 
pplled for 50 cycles, use 
titer fi.150 or O-ano volts. 



TKAHSISTORISED UJSTJ. 
LATIOJi TESTER. On* 
handed onoratioii, no crank- 
ing of ((eoeralor. 3 testing 
voltages 100. 2B0 and 500. 
to measure up to 500 
Megohms, Complete with 
leather carrying ease and 
test fcada. ONLY Sl?.10.0 
□lustd. ,1c tails on request. 



SUPER CRYSTAL STICK 
MIKE, complete with heavy 
desk stand neck cord, and 
screened lead. ONLY 49/B 
(Post 2 fti). 



aPRAGUE C0NDEKSEB£. 
Metal iswed, wire end, Sew 
0.1 inKd. 1,000 volt, and 
».l mFil. BOO volt. 7/8 per 
dozen. 8 peel* i quotes 
tnr " nan til lea. 



PANEL METERS 

1 D.C 'Jliu. ProJ. 
otropjar 59/6. SO mieroamp* 
!'lu3h circular, S9 8. 
100 udi'toamps. D.c. ujln, 
Flush circular 39/6, 40 amps. 
i».U Win. Proj. circular. 7/t. 
000 volt* A-G. 241ij, Flush 
circular, S557-, 



MOVING COIL STICK MIKE, 
complete with heavy desk 
stand, and screened lead 
ONLY 59/fl < post j.-iii 



A0OS 09/ 1 STICK MIKE will, 
aoftMnad lead and table stand 
ONLY 3S/8 (post 1,6). 



CRYSTAL DESK MIKE Dtt 
screened lead and buOt-uj 
ONLY 15/- <r^at I 'i> 




15 OHMS P.M. SPEAKERS 
Special Heavy Duty iah». 
£S.K.O. 

Whariedale W12EG lain, 
(or Lead Quitars, £10.10.0. 
WhartBdale W15EO 101c. 
tor Haas Guitars, £17,10,0. 
12in, wedge type speaker 
cabinet, IE.17,6, (Pteaae 
add SI- can. an item.-.) 



fiLSIilOKii. If 



, New 7/fl.l 10 



CONDENSERS, 100 assorted 
and silver mica. NEW 



VARIABLE VOLTAGE TEANS- 
FORMERS. Fully shrouded. 
Input 230 v. A.U."af)/00 cycles. 
Output 0-S60 V. 2,15 aiDpa. type 
£6.17.8, 5 amps, type "fj. I 
10 amps. type £16.10.0, Brand 
new Import, fully guaranteed. 
Immediate delivery and service., 
Hi unrated details' on request. I 



LINEAR AMPLIFIERS. LG34, 4 watts, else 8ix4fx2Kn. high. £6.5.0. L45A 
8 watts die 7x7xJl B . high. £5.18.0. Protective cover, tm. iSwB watS 
%^T Q \t t i . . lX ^- X 5 to ^ lKn - * 1£ - la0 - «*«' ™ th "•''U* indies as/-. 

VZ '\ 7V~ „?, J t b %?i}?X h *"<«<««i 18/B- Ll^lO 10 watts Hi-Fi Ultra Lineaj 
in ,*.»' bi ;•!?£■ G ?; 1S -°- Cov «» "***>■ carrying handles. 18/8. ■TOmchohi" 
JLlfaih^f k^ f'SfX " i " W*x»x7*in. high. £18.18.0. Cover with 
oarrying handl B .JS^ Lao 50 watts Hi-Fi Ultra Linear, die 14 x 10 X 8in. high. 
I83J.0. Cover with carrying handles, SB/8. All amplifiers for normal a!c. 
mains, ami el stock. Details on roqueetT^ ^^ 



20/- iflftSTiillCTOR'S PAStEL, 
Assorted incurs wiring „ 
er resistors, condengent 
me roctruls, laie panel. 
ALL WFW 'r.ost 2^B1. 



"Triplelone" ConterUite Ampuller, site 10x3x4 t ln. high, 4 watts output 
BUM e ^ °^ ° B a ""P" *" «»» * «™»W toletber te STEREO, 

(unpow=r*d). or £15.14.8 (sett powered). Detail* on retroeit. 



^SS™*??, F ?F Q ^ EK SS. "E™ 1 ^ TYPE LM14. Freo.i«ney range I 
1 2/.-GO,0O01 fcc/sln 2 lainda. This is tne United States Bary Model of the w3l~ I 
tnowu BC221 Frequtney Meter, but has many additional features which Increase I 
Its usefulness. Voltage sUbilisatlon circuits and Crvstal control ensure extreme 
accuracy and In addition it Is fitted with on Internal Modulation switch to afiow 
u*e as a Signal Generator. Size only 8, x8 X 8iln. FuB information on request.) 



HARRIS ELECTRONICS (London) LTD. 
138 GRAY'S INN ROAD, LONDON, W.C.I 

Titeph** TEXmintu 7887. eiwtt include earrio^t owmiU iUm* 

Open until J nji, Sisurdayi. We in 2 mlo*. from Higo Holborn (ChaaoBy I 
Laos Station) and S mini, by bus trom King-* Croat, 



de^ , n«d ^ L l 'r,V' : ^^| iG i N -^^. c ■ t 5 I:RA1 ' R■ Handsome well 
aeajgnea instrument, ex U.S.A. Forces 100Kc/-i to laoivt^fu nn 

lmr^ m a entalS ,-, J0 <Uw » c Si ls ! ^llbrated rwgesfc MHEfflE 
f«»i nffi., a e !i sc , r /ene>d ladder, attenuator, variable carrier 
£Zs l ( . 1 ??^ A monl tor meter), stabilised H.T., IntT modTBi^ 

^rt^ttl eE f f ro ^i ne wav emeter. In flrst-^lass condition, tested 
u-oin us v a l„ so c/s (suitable auto transforrrer for 340 v 
A c. operation, tVB extra). PRICE ONLYng. Can-. 10/- 






R.C.S. PERSONAL SET 

DeslgTied for personal listening- without 
disturbing' others. Supplied complete 
with battery and earplece^ — no extras to 
buy! Sensitive one transistor diode 
circuit ?Ives quality reproduction over 
mealtun wave band. Attractive case 
with large tunlnn dial. Ideal for use as 
tape tuner. Slzeoniy nn/ep g,p 
31 x gj it lip. ONLY **/0 a/T 




Cha™i^»™L P ^^ k Plnest l"^" Canadian with 
and tar-lr n)„ m ^M S 1 n<I loat , he >: covered headband. With lead 
BRAND new f.". e etoludlng, supremely comfortable 



ATAGXETH' COUNTERS (PX-GJ> 



SbR?V ,s SAV I'll'-MEHS (ox-G.P.O.) 4 fUrures m Qoo rv.de 



■OCRO-AMMETEa. 0-500nA. Made by RCA Weston 
Circufafa.'in 6 -^^ S£% I™ ?? AmerlcL "ma^factu^ 
O^liStl A.nirtK mount nrr. Dials are engraved 0-15. 
TESTOAnI? ^ARANT^^nr ™ nd0B ° f th& " W SET " : 



HEAVY DUTY TRANSFORMER, Input 220 to 250 volts 4 C 
mains (capped every S voltsl. Output SOV at 15 amos A reaiiv 



wlLiS. .?2? la - T lP- to P condition, complete with rrystal caU- 
ptr5 Rt-rt ? .'v^« B ^ RGA ^' F0R Callers o'nKy: nn. 
wave ->™ i^M^S;^, 3 wavo r? fttl J ls - raedl1111 ' «-avo and 2 short 
p™ ?-,IT om . i?°- 13 metres. Good condition, tested, 8 gn^. 
Cbjt. 10/-. A-C. mains Interna) power supply £g extra! 



BATTERY ELIMINATORS 

T2 ie ™'? eal economjcal and sale way ol runuins anv lit a v. 
AMW^^?'^ RKCO « D PLAVF.U. TA^LREt^OItDER; 
A\U*LIFIER, etc. requiring voltages shown. 

^I^fin^RTcEloTeac!,^ 1 ^^ Wf talngleou ^ t >- •< 

i& r av at rUz^^vhy!*™* 1 ' ouEIlut3, ■ 

^ub?eVord%^sforXr^Xf^ y i00^S y from malas by 



LISTEN TO THE WORLD on TELSTAR our l-VALVE 
SHORT WAVE RADIO 

Receives speech and music 
■rom all over the world. Price 
ncludes valve and one coil 
covering :o-ioo metres. Can 
l:e extended to cover 10-100 
metres. Can be converted to 2 
or 3 valve and all-mains 
speaker upe. Tota. Building 
Costs 35/- p . & P. 2/-. 




CHARLES BRITAIN RADIO LTD. 

1 1 UPPER SAINT MARTINS LANE, LONDON W.C.2 

TEMpft Bar 054q 
6iwp twun 94 p.m. (9-1 BJn.Vhuradau). Open all day Saturday. 



R.C.S. CRYSTAL RECEIVER 

Covering medium wave band. Ideal for the 
EWfflnner! All components in- Q fe P & p 
eluding case. fl/O i« 

(Suitable headphones 9/6). Easily converted to 
1-translstor or 2-stage transistor receiver. 



At I ports available separately. 




R.C.S. PRODUCTS (RADIO) LTD. 

I Oliver Rd., London, E.I7. (Mail Order only) 

.^^ ^^_ Export Trade Enquiries invited . 



388 



PRACTICAL WIRELESS 



NOT TO BE 
MISSED 



BARGAINS 

Filament Transit) rmer. l-2"volt 11 amp stand- 
aid mains lupin easy to! adapt tor other 
voltage?. 6(8 eeoh. Pins 2.'- p» 
Waterproot Heater Wire. 16 ydt. length, 
70 ifbUid. self regulating temperature control. 
10/- po*L free. 

Beliifteratot TUermoEtat Standard type with 
adjustment for all normal refrigerator 
temperatures, 7/8, pine 1/- post, 
Slmraetitst Heater Regulator. Suitable to 
Miptrol elements, heater, soldering Irons and 
Dotting rings up to 2,500 watts. Complete 
adjustable, normal price 55;- each. Special 
■nip price 12/fl. plus 1/8 postage and iturar- 
moo* 

Pre-AiaplifleT. Made to Mullard design to salt 
the 10 watt amplifier, made to specification. 
Sew Unit. Simply needs Yalvea. Type EFS6, 
S7/8 eaeli. 

46 Set* (Eeeelver/Traoamitter pack set). 
Boosed seta complete except for orywato. 
Packed with parts and easily rebulldahle rato 
other gear. 19/6 each. Post 3,'-. 
Haini Tnaalormer. 250-0-950 at 80 id A. 
6.3 volts, I> a. (normal mains Input). JE/6 each 
Carriage 9/8. 

Ontpnt Transformer. Standard pentode 
ma tolling type. 3/6 each. 367- Per do1 ' 
Vibrator Transformer. Suitable tor 6 or 12 
volte Input, 6/9 each. S3 per doz, 
Slide Switoh, Sub-miniature but dpdt, S/6, 
each. 18/- per doz. 

Battery Charger Beodfler — selenium 12-15 v. 
5 amp. 9/6, 

Metel OhaM la— punched for Mullard 510 
Amplifier, complete with toner screening 
■ectiona and atove enamelled, 18/6 set- 
Twin TwUled Lighting Flei— equivalent 
14/86, rubber insulated ootton covered 
13/6 per 100 yard coll. 
Moving Coil Uetera 
0-500 mlcroamp- 2ln, flush , . 
260-0250 miCToamp. 2ito. enrfaoa 
750 microamp. 2tm. surfaoe ., 
0-30 milliainp. ilm, Audi 
0-100 mllllamp, 2 tin- flush . , 
Wheni postage i» not ueflniteU state* add 
£/- all orders under £3, 



GOOD COMPANION 

Mark NIB 

The 6 translator set with the 8 
transistor perforxtiauce. 
Incorporating ail the latert r<- 
iiuu-ements. Anyone vha cau 

solder ■/in make it. ttany thousand" 
already In use all over ihe country. 
Full coverage of l*>ng and Medium 
wavebands. 

Fine looking rabinet, size 11 I o 
x 3". y.P.P, Output apprul, 
7.5u m'W. I'A^ltalt reception nf 
difficult stations like 20S, 
Variable ii-ed back gives excellent 
tone. ONLY £6.19.6 

Plus 41- post and insurance. 



THIS MONTH'S SNIP 
Complete kit of parts to build 
this 6 transistor 2 wave Loud- 
speaker receiver at only 39 6. 

"CORONET" MK. Ill 

It fully covers the medium waveband and 
that part of the long waveband to bring in 
BBC 1 fghl. The circuit includes a tugnly 
efficient slab aerial and Plessey tuning con- 
denser. Overall size approximately 4 s J * s 
IM11. Supplied complete with carrying case. 



17/9 
27/6 
17/6 
17/6 
15/- 



CABINET & PICK-UP 

Made for a famous company 
intending to make a Battery 
Record Haver but changing their 
minds. This Is an extremely Hue 
looking cabinet, must have cost 
st least £2 to make. It is complete 
with bandla and fasteners as 
Illustrated. Also Included in the 
parcel Is a Coamocord pick-up 
with crystal cartridge and sapphire 
stylus. Both items new and per- 
fect. Only 19/8, plus 4,'S post and 




August, 1964 
Building A 'Scops 







3to. oscilloscope tube. American made 
tvpe No. 3FP7, 6.3 v. O.tS amp. heater 
eject roslallo deflection, brand new and 
guaranteed with circuit diagram oi ■scope, 
16/- each. Plus 2/6 post and insurance. 



YAXLEY SWITCHES 

Complete range available. See Jane Issue 
or send for list. 




Fishing Rod 

from 
Dinghy Mast 

Tubular aluminium not 
separate sections, 

extends like telescope 
from 18 Ins. to 9 ft.. 



MOTOR BARGAIN 

Silent running mains 
motor by very famous 
maker, ideal for 

gramophone, tape 

recorder, fan etc., etc. 
HMM volts, A.C. 
shaded pull atari. 
slae approximately 
!J X 2, I llin. 2,750 
r.p.m. Spindle dia- 
meter 6/SSJu. epindlt 
length {In. Brand new 
arauteed. Prl 




ELECTRONICS (CROYDON) LTD 

" ..- . n ^. nnu en&n WEST CROYDON. SURREY 



'266 LONDON ROAD, WEST CROYDON, SURREY 
Post orders to: 43 Silverdale Road, Eastbourne, Sussex 




H A C were the original suppliers of Short - 
Wave Receiver Kits for the amateur con- 
structor. Over 10,000 satisfied customers— 
[ifiludtafl Technical Colleges, Hospitals, 
?nblie Schools, B.A.F., Army, Hams, etc 

IMPROVED 1964 EANGB 
l.V«lve model "GX", complete kit. Price 84/8 
Customers sav: "Definitely the best one- 
valve S.W. kit available at any price. This 
kit contains all genuine short-Wave com- 
ponents, a drilled chassis, accessories and full 
instructioni!. Beady to assemble and, of 
course, as all our products, fully guaranteed, 
FULL RANGE of other kits still available 
including the famous model 'K\ price 77/-. 
Before ordering call and inspect a demon- 
stration receiver or send for a descriptive 
catalogue and order form toi — 

"H.A.C." 8HORT-WAVE FRODITCTS 

CDwt. T.HJ, 44 Old Bojid St., London W. 



FUN WITH 
TRANSISTORS 

by Gilbert Davey 

edited by Jack Cox 

Explicit instructions in 

how to make all types 

of transistors & appliances 

Illustrated I2s6d 

KAYE-WARD 
194-200 Bishopsgate EC2 



, 



Audio — UP. — R-t*- Oscillator. Simple 
square wave circuit giving output at audio 
freauency. aad over the whole radio spec .- 
trum up to 1.5 Mc/s. Use for rapid-dead" 
set testing, use for morse practice etc. 
Variable amplitude. Basic kit comprises 
transistors, condensers, resistors, tag 
strtpSpot. switoh. knob. Price 10/-, Post 
If-, with circuit and instructions. 
Precision WlMwoiaid Hesisjors IVY. 
1 ohm to 5K 1% 3/-; to 2DE 473: i% add 3d. 
Your value wound to order 
ti ii!ii s^tub Resistors. iW 1% Si/-. Full 
iXSlari^SiWB 10 ohms to 10M plus many 

?i e e C t^ g^tift"rNew J falford f.w. bridge 
^I^WlWI opv 33/- Post 
1/6; EP10K 10,000 OPV «9/6, Post 1/6, kP30K 
30 000 opv 99/6, post 1/6; EPBOK 0O.OOO 
opv £6.10.0. post 2/6. Illus. leaflet avail- 

Cr'ystal Diodes or VVestectora, tested, 
guaranteed. S/6 doz. Post 6d. . 

New Miniature Meters. 50uA 39/6. 1mA 
27/6. internal resistance measured IT re- 
quested. Post 1/3. __.— _-. 
PLANET INSTRUMENT CO, 
25 DOMCSION AVENUE. LEEDS 7 



PETHERICK'S 

FOR 

REPANCO COMPONENTS 

DRXI Cryiwl Set Coil M & L- With 
circuit, 3'-. . , „ 

DRRZ Dual Range Coil with Reaction. 
Boxed with Valve wd Transistor Circuits, 

4'6. _ 

TT49 Transistor Interstage Trans- 
former, S'-. 

TT4S Driver Transformer, 6'-. 
TT46 Output Transformer, 6'-. 
FR2 Ferrite Rod Aerial M ft U. wnn 
circuit, I2'6. . , _,..,,. e i, 

FS48 Ferrite Slab Aerial TRAWLER 
BAND, 7'6. „_ __, ,. 

AF2 Audio Choke 200M h C.T., 6'-. 
TT23 10 Watt Transistor. plJsh -); u ' , 
Driver. Transformer with Circuit, 12' 8 ' 
TT24 10 Watt Transistor. Push-Pull 
Output Transformer with Circuit, Zl'». 
TTSI Transistor Invertor Transformer. 
12 v. D.C. to 240 v. A.C. with Circuit, 31'6. 

TRANSISTORS. 
GREEN SPOTS I '3 each 3 for 3r3. 
RED SPOTS I 'i each 3 for 4'-. 
WHITE SPOTS 2'- each 3 for 5'3. 
MAT 100 7'9, MAT101 8'6, MAT 120 7'9, 
MAT 121 8'6. , , . . 

TRANSISTOR HOLDERS 3 or S ptn 

WIRELESS WORLD VALVE DATA 7 '4 

ALL SENT POST FREE IN U.K. by 

PETHERICK'S .BK8. 

22 HIGH STREET 

BIDEF0RD, N. DEVON 



Tel: Bideford 1217 



August, 1964 



PRACTICAL WIRELESS 



389 



Raaafl Bbop) 



Z & I AERO SERVICES LTD. 

Head Office and Warehouse : 44A WESTBOURNE GROVE" LONDON W.2 



TOTTENHAM COURT ROAD. LOMDON W.1 

tit.: LANfbim 8408 



FIRST 0.UALITIT ELECTRONIC VALVES FOB BX-STOCK DELIVERY "'"" 

4/B8AM5 S/6 0X3UT 5/6 25Z4G 8/9 A9888 17/6^30684 6/8 EM81 



TV/.; p.4/e/c 5641 ;z!3 



llZ-iiAMB 
61- OASl 
6/6 tiA^i 
51- BASti 



OA3 

.!):■_■ 
Ol .. 
QDJ 

024 

1A3 

IASGT 4/6 n ALB 
I A7(IT 7/- BAYB 
I AIM 7/-HB7 
K.'iGT 7/-.BBS 
1G8GT 7/-6BA8 
ItlSUT 7/-I8BKS 
1R5 6/-0BF0 

4/6t:BHii 
«/BgBJB 
3/-'8BJ7 



4/.7B7 
15/- 7( US 
8/- 7 I'M 
5/-' 



5/- 6AS7G 2S/8 7F« 
8/- SAT6 1/- 7Q7 
6/-TY4 
6/- 7Z4 
8/- ttBWfl 
6/- IO(.'l 
4/8 1001 
B/- 10 F9 
8/.IJ0U 



S/- 8BC15 

8/-30C17 
7/- 30 F j 
7/- 301.17 
4/. 30F12 



8/-2JZ5 T/-|AO/TiU14/- BCOBs 8(8 K\H1 

10/- ar.ZiiOT 8/8 Al\T4 7/fi EiXJSH 9/- KVk:. 

8/- 8901 80/-AZ31 8/-ELFso 7/8 EM >> 7 

8/fl < ' I O B/- ECF32 7/- fix J 1 

U/-CG10P. 1/6EOFS6 H/- em ay 

8/- CL33 B/- ECH-il S/- EMfJ 

18/-OY31 6/8ECH33 10/-EYSI 

- 10/- IiAfH 4/8 ECH42 7/- EY*l 

7/-30PI9 14/- t)AFtW 67-ECHHl 8V- BY-i:l 

10/- 8BA5 1U- L>AF90 6/6 EOH.83 7/8 EY84 

./-^■LOUT 8/8UF33 B/- EOLSO 6/- EYSS 

B/- 33W4 4/8 DFB6 8/- RCE8S 8/8 KZ4U 

7/B.35Z3 10/- DFftfS 6/6 ECL83 9/- lii:41 

8/-U0H14 1B/-:36Z5GT 8/-OK40 11/- EF6 7/-KZ31 

Swiri on "■I, 1 ;? ZfcffiB!? 8/--DKPI B/-EF36 4/6 GZM 
0/- 8BK4 80/-H115 7/-30C5 8/- l>J£»a 

7/--BBB7 11/6 12AH7 6/-50UGT B/-UL6S 

W-,8BKfl S/-.WAH8 11/. SO tl-DW 

9/- 12AT6 */-*3 8/- 1 1 VI 7.) 

8/-IBBW7 B/-!12AT7 3/-.8SV 7/8UV-it 



iFCL-aa e/a usa 

7/BPCJ.83 8/- I 
8/- PCL84 



8/- PCLX3 
8/8'PCI>i8 
10/-PL38 
10/- PE3S 
8/-PL81 
7/- PLS2 
7/- FLS3 
8/8 PLS4 



7/- i/aa 
e/8 i 3i 

«/- I Ml 

8/- I id I 

ie/- L'jsi 
7/- uani 
s/8 uaaa 

B/- I' 301 

B/a i -ins 



B/Sii-jAro 5/a «al> 

8/.!l-2AUT B/-90CG 



1S4 

in,-, 

1T4 
IL'4 
I US 
IXSA 
1X8B 

90*1 

3A4 
3AJ. 

3H7 
3 D.I 
304 

:<Q.x;T 6/8 

3»* 6/-i3F13 

8V4 5/60F17 

8B40Y 9/-8F33 

BL'40 B/- 0JS 

6I.4OB 8/-3J8 

4V4U 8/-I8J70 

SYwT 6/-HJ7GT jfalBH}7 10/- 954 

5K4 : /-'(JLB P/-l:UJ3 6/- 955 

6Z4UT 8/-0i.ao 6/-1UAQ5 6/- 937 

BAM SK0N7 8/-19BU8U 7/-!9SSA 

8AB4 6/a0(J7O 8/.20F2 1B/-:9S9 

8AF* H/-.BU4GT 10/8,a0Ll 

8AQ7 5/-;SU7G 10/-20PI 

8AH8 11/-'8V6 B/- SOPS 

SAKS B/-8VBO 4/-'Ji.l'l 

6AKB 7/-SV6tiT 7/8y5A.-.G 



7/6 PL500 13/ ., 

6/8 PM54 10/-1 40'TO 

5/6:PTlo lO/.'UAtMS 

8/8PY33 10/-UB(J4l 

B/8PYSO 4/9 CBC81 



6/8 EF37A 8/- (izrta 
B/B EF39 5/- GZ44 



8/8:UYtJB 



10/- EF40 
S/-EF41 
6/- EF4-J 
7/- EFSO 
7/- EF83 



4/8.1" YRl 
18/-JPYB8 

10/- PY83 
10/- PY>>S 



6/6! I, BFSO 
6/- UBP89 

6/- i-KL'Jl 
7/8 1 I i v t 



)/»iiZ37 8/-PYMM B'6 1'i (■»;, 
1/8. KT' "' 



eo/-.EflSCC 15/- EF95 
IBZ-iEdlll IB/- EI'Mi 



8/-S5B^V7 
8/6|tiL'4 
7/- flCBG 

Iffi85° l ti m 72 A S Z(- ;Bnc V W-IEBIH 1S/-EFS0 

eitf? ,S'H*U 8/-,l.WE2 12/.IE9.JCC 7/-EF99 

I 10/- I-JAX7 6/-,130B3 8/. KlS0t.11 10/- EF9M 

4B1-AY7 10/,-jaoTH 8/.JBl*iP 15/- EF18S 

G/-llBEd 4/6 Sit 
8/-li»R7 B/-813A 

3/at-JKI 20/-KSJ 

4/- 1'JKS 10/- S68A 



6AL8 3/- 6X4 



ia/-:sflS7 

14/- 3098 
IB/- 3763 
14/-'fi0«0 
S/-6060 



.T»C B5/-;PYS01 8/6 l.TFSO 
8/-IKT0B 1E/-PX25 10/-i:CH21 
5/- KTtfl 17/8IPZ30 10/- L'CH4a 
fl/8|KT8J* 80/JQQYOa-8 1LTCB8I 
6/-'KTW'aM 7/-| 88/-UOLB3 

6/8 N7H 15/- QQV03-yOA UCL83 
4/8'0<:P71 24/- 86/- VI'U 

B/-OKP12 12/- QQVO6-40 I.F42 
7/-OEPBU 18/- 70/- UF80 

■ 7/.PABC80 7/-E1 S/-t"FHS 

8/- EABCS0 8/- EFPfiO 10/- Pf.«!ti IB/- R10 
30/- H\tiJ 8/8 EH90 7/-PWHK 12/. K17 
JS/.EB41 8/9EU4 10/- PUD7 8/8 R 13 
80/-E8C3a 8/-ELAJ 0/- PC«.»4 B/6H19 
2 J{' ^i"-'* 1 B/B.K1^7 17/f:POC8fi 7/-KI.S8 18/8 I M-il 
6/-E1KHI 8/8BL3S 17/iPrOW 10-T41 15/- I v-j 
8i[.KBP«(l 6/6;EL41 7/8IPC(JrtO 10/-TH41 10/-IY41 
7/- fi 'U L.^H 10/- TH288 8/-! U Y85 
8/8: PCF80 5/6 THMai - 7/- W81M 
7/.!WJfc'flS B/a.TF'iii 4/8iX03 
B/-PCF84 lOZ-TPa. 1 ; 4/- SOB 
7/- PC1'8»; 8/- TP2620 7/8 \79 
7/6 PCFSOl 10/- TT16 86/- /X.:\ 

i9 10/- TT-il 38/- K7O0U 
8/8 FCKx.,,1 15/. TT-32 32/6 K 



13/- I F8B 
BJ-llVj 
7/8 IU1 
6/- ILS4 



6/-,EBF»S 7/- EU'J 

4/-IKBF89 B/-EL81 

8/-!EBLl 15/- EL83 

B/- KC{i3 12/6 EL.S4 

8/- BOBS 18/- ELSJS 

10/- BXJ89 6/- E1AH 

6/-EI-CS1 3/. E J. 8*2 

85/- ECCH'J &/-EM34 



wmt&m msm b-j:^ WRIZ* 1 ?,:^*!,'.^,- 



AU our T»lr« clmT faU ■touttotur.n" gn»r»nt«. An, ! 1U ]t T jttm is replaced immtdiitely im ol ch»r« 



8/- 
12/- 
11/- 
3/6 
5/- 
11/- 
18/8 
13/- 
18/- 
11/- 
7/- 
20/- 
6/7 
8/- 
8/6 
7/- 
6/8 
7/- 
11/- 
8/- 
8/- 
B/8 
8/- 
7/- 

7i^ 

s;- 
m 
n. 
m 
m 
?'- 
& 
m 
K 

al 
u 

4/6 
5/3 
if. 

s/- 

iS.- 

u. 

5;- 
bS- 



STUVISTOES 

ijCW4 (or V LTI' ttmen and T.V. 

tiiiifrji 141. 

JCW ., 14/- 6D34 * 18/- 

'580 . . £8/8 7 SM __ ffi , e 

Bwi (or XuvlstorB : . 8/ B 

8EMIC0NDUCTOB POWER 
RECTIFIERS 

Gprrimiilimi sluiI maimved 
GJ3M, 200 ii.l.v., 000, 1000 

■HAD.C each 8/8 

Bel of (our 18/8 

Sillfioa Wlro Emler] sab-minia- 
ture, Lire AS DD05S, BOO 

. p-l.v., OOO uiA D.C 18/8 

Silicon atuU Mounted, BYZ10, 
?iQ0 p.:. v., a ampe D.C. . . 7/8 



OC26 

ooea 

OCS8 
OC44 

CTC46 
Ol.'7ll 
OC71 
0079 



TRANSISTORS 
S/- 



CK. - 78 

OC78 
OC78JB 

OC1S9 
OC170 
OCJ04 



1718 

lt> 

0/- 
5/- 

Q. 

. 8/- 
iiet ot two motclied OC81 and 

one OC4ili> 
GET11S . . 7/- GET573V. 
R.C.A. 2N4J0 <OC4S) . 
'2X412 (t>C44) .. 
TexaeS-P-N-, ->i<0O4 



8/- 
«/- 

7/- 

7/- 

18/- 

8/- 
10/8 



18/8 
£0/- 
8/- 
3/. 

10/- 



ii.2AW ZENKER DIODES 
VRiiS (4.2.7 \ i: VH475 (4.75TJJ 



VR3S5 (fl.KSV); 

vKBya <*.a6V)j 

VK9B (9.0V) . , 
VR10B (10.0\1 



VRB70 tS.73V>; 

VR7B (7.0V); 

. .all at 6/8 

1- • ■ V- 



RABI0 FREQUENCY METSRS 
350mA 2(n. round plng-in . . UJ/t 
1 imp ttJlD. round projecting . , 16/. 
2.5 ampe, iln, round ar =iju*r* . . 25/. 
3 .0 amps, a I d, round or square . , 88/. 
4.0 aiHT*. 2in. square . . ' 20/- 



Plaue add 2/8 In 3 lor postage and budllng 



THE LATEST EDITION OF ENGINEERING OPPORTUNITIES 



Hiive you sent for your copy? 

ENGINEERING OPPORTUNITIES 
is a highly informative 1 56-page guide to 
the best paid engineering posts. It tells 
you how you can quickly prepare at home 
for a recognised engineering qualification 
■nd outlines a wonderful range of modern 
Home Study Courses in all branches of 
Engineering. This unique book also gives 
full details of the Practical Radio & Elec- 
tronics Courses, administered by our 
Specialist Electronics Training Division— 
the B.I.E. T. School of Electronics, explains 
the benefits of our Employment Dept and 
shows you how to qualify for five years 
promotion in one year. 

We definitely Guarantee 
"NO PASS -NO FEE" 

What «"er you rage or experience, you dnnoi afford 
to mm leading this famou. book, if you are 
Mmin; lets thin £ii ■ week, send for your 
J&WreI 1NMRJNG OPPORTUNITIES" 



WHICH IS YOUR 
PET SUBJECT? 

Mechanical Eric.. 
Electrical £ni , 

Ciitl lireinetrint, 
(tidfe EnelntcHne. 

Automobile En(., 
Aeronautical Ene.. 

Production Ene,. 

Bu. dine. Plaatict, 

Orauthtsminihip. 

Ttltvlsion, lie. 

GET SOME 

LETTERS AFTER 

YOUR NAME ! 

A.M.I.Mech.E. 

A.M.I.C.E. 

A.M.I.Pred.E. 

A. M.I. M.I. 

A.l.0.8. 

A.F.S.As.S. 

8-Sc. 

A.M.Brit.l.ft.E. 

City & Guilds 

Bin. Cart, of Education 

Etc., etc 



EQUIPMENT 

Basic Practical »nd Thssn. 

tit CeurMi far b.(inn«r, , n 

Radio. T. V., Electronics, In., 

A.H.Brii.l.R.E. City 8 Cullda 

Aadio Amateurs* Eaam. 

H.T.E.8. Cartiflcit* 

P.H.G. Ctrtllieat* 

Practical Radio 

Radio 8 Television Servicing 

Practical Electronics 

Electronics iEnaincering 

Autematien 



INCLUDING 
TOOLS! 

Tht iptcialitt Elic- 

rromet Divitian of 

B.I.E.T. 

NOW o0m you a 

'•ali'aierarory irain- 
int at hem* vtiih 
practical tauipmm!. 
Atk for dttaih. 

B.I.E.T. 

SCHOOL OF 

ELECTRONICS 



MUST COUPON MOW * 



Pleise sand me your FREE 1SS-pa|e 

■ "ENGINEERING OPPORTUNITIES' 

■ (Write if you prefer- not to gut page) 

■ NAME 



ADDRESS.. 



BRITISH INSTITUTE OF ENGINEERING 
TECHNOLOGY 



(Dept S E/21 ), 29 Wright's Lane, London, W.8 





390 



PRACTICAL WIRELESS 



August, 1964 




TRANSISTORISED 
MORSE OSCILLATOR 

Fitted 2m. Moving Coll Speaker. Uses 

type PP3 or equiv. 9 v. battery. Complete 

with latest design Morse Key. S3/6. Plus 

1/U P. & P. 

SEMI-AUTOMATIC "BCG" StPEft 

SIM.KO MORSE RKV 

7 adj ust- 

m e n t s . 

ar««l8ion 

tooled. 

speed ad- 
justable. 

10 w.p.m. 

to as lilg-h 

as desired. 

Weight 

2Hb. Price £4.12.6, post paid. 

BUILD AN EFFICIENT STROBE UNIT 

FOR ONLY 37/6. 
The Ideal Instrument for workshop, lab. or 
factory Tnis wonderful device enables you 
to "freeze" motion and examine moving 
parts as stationary. We supply a simple 
circuit diagram and all electrical parts in- 
cluding the NSP2 Strobe tube which will 
enable von to easily and Quickly construct 
a unit for infinite variety of speeds, from l 
flash In several seconds w stivei-al thousands 
per minute. New modified circuits bring 

Tirlce down to 37/e plus 8/- P. & P. 

XSI'2 CVK9S STROBOI 'RON' FLASH- 
TUBE made bv Ferrantl. brand new, l.O, 
base. Price 15/-. P. & P. 1/-. 

MAGNETIC COUNTERS 
10 IMPULSES PER SECOND 
TYPE 100D, 1.1 ohm coll, 3-6 v. 
DfC Operation, TYPEHHJA.oUU 
ohm coll, 18-24 v. D.'C, operation 
TYPE lOflB. 2,3fX) ohm coil. 3S-4H 
v D'C. operation. Any typo 
15/. each. P. &P/1/0, 

VARIABLE faun 
VOLTAGE fd 00 

Post Paid. 
Input 230 v. A'C. Output 
O-2G0 v. at 1 amp., lul \ 
shrouded, new. Also available 
2 5. 5. 8. 10, 12 and 20 amp. 
Write i'or details. 
SEALED UlLcH 




m 

1/8 

a/9 
«/s 



fl/8 
4/- 

w 

3/9 
1/9 
6/8 
13/B 
-6(L 

Bd. 
LClil. 

fid. 

2/9 



COMPONENTS 

NEW, TOP QUALITY. GUARANTEED 
Moulded mlvebolders B7G, B9A, Octal .. 84 
Air Bpaued variable!, aiuiill, 17 prd, oO p*d, 

1150 pFtl, 3B5 pi'd 

sh i-i <»i-.i'hc< s y 

Blow motion drive with dial flunga . . , . 
■in. dial 0-100 to fit above . . . . . . 

llL.in-i t.riinsiumiers, fully sbrouded, 1150-0-2=0 

liO iiiA, ii.3 v. a amp ,. .. P. *P.2;» W/- 

MldK^i SSa v. 40 tuA, 6.3 v. 1 amp P. * V. UI3 14/8 
Cuuiacl rectifiers 1 s. tin. 250 v. 50 mA . . " 

in tan JF. Trans, high gain, ierrite cores, 

pre-aligned pair 
I meg Volume control* D.P. switch . . 

iesa switch . , . . . . ♦ > 
10 1-lS tnFd, 450 v.w. eleottolytica .. 
6 m Fii, 350 v.w. small .. 
Mlilget smoothing chokes lOh. 60 mA 
High sensitivity speaker units oln. 3 ohms . . 
0.01 mFd 40(1 v.w, tuhulat 

0,1 mJr'd 125 v.w. . . . * . - »« 

0.1 uiFd400 v.w. .. .. 

J uo pFJ, ceramic • • ■ 

OA81 diodes . . . . . . • ; ■ ■ • 

SK ohm edge type ■volume controls with 

switeh, white ■ "HJ" 

i;.-»i l -..u!i-d solder U 

Oo-ax sockets .. ■■ JJJ 

Oo-ftX plugs . , . , . - •■ •■ *'," 

High sensitivity Headphones, 4000 onma . . ad/- 

B. ELLIS 

7 RECTORY FARM ROAD, SOMPT1KG, SUSSEX 

PSP charge 1'-. Cash with order, no CO. D, please. 
Cash refunded if ooi completely sat tarred. 



BBC2 (625 LINE) TV AERIALS 




transformer' 



SPEED 



12(8 

ism 

12/6 
12/6 



SIEMENS 
RELAYS 

H96A. 2.2 ohm +2.2 ohm. new 

H9SB. SO oim+50 Ohm, new 

H90C 145 ohm +145 ohm. new 

M96D. 500 ohm+500 ohm. new .. _ fiis 

H96E. 1700 ohm +1700 ohm, ex-equip, lwo 

SOLENOID. Overall length 3im.. stroke 

ijn, to iin. Maximum push 8oz. l2-2*> 

DC operation. D C. resistance 35 ohm. 

Price 8/6- P. & P. 1/6. 

VAN BE «HAA^^ i ECTRO-STAT.r 

■with Motor drive for 
230 v. AC. giving a 
por.em.ial of approx. 50000 
volte, Supplied absolu- 
tely complete, including 
accessories for carrying 
out a number of interest- 
ing experiments, and lull 
instrui ■:-U ■.!]-■=. This instru- 
ment Is completely sain, 
and Ideally suited for 
S oho o 1 d em a u s 1 r atl oiw . 
Price £6-6.0, plus 4/- 
F. &F. 
.^.CIGHT SENSITIVE SWTTCH- 
Kir. of parts, including ORP .12 Cad- 
mium Sulphide Photocell. Relay, 
Transistor and Circuit, etc., price BS/* 
plus 2f6 P. & P. ORP .12 including 
circuit, 10/6 each, plus 1/- P. & P. 



RES'CAP. BRIDGE p 3 ?^ 

Checks all types of resistors condensers 

6 RANGES 
Built in 1 Hour. Direct reading 

READY CALIBRATED 
Sump for details of this and other kit*. 

RADIO MAIL (Dept. C) 
Raleigh Hews Raleigh Street, Nottingham 





EXTERNAL MAST 
MOUNTING ARRAYS 

9 element 45/-". 11 element 55/-; 
14 element 62/6 
VV4LL MOUNTING with CRANKE1) 
■VRM. 9 element 60/-: 11 element 6/76; 
14 element 76,-. CHIMXEl ARRAY h 
with LASHINGS, 9 element 72/-: 11 
element 80/-: 14 element 87/6. ';«£,[ 
\ RRAVS. 7 elemem; 32/6: 11 element 62/8 
14 element 70/-. Co-ax. Plugs, 1/3. Low 
Loss Co-axlai Cable, 1/6 yd. 




OC41 
OC45* 

OOTO* 

oc7a 

OC75 
OC76 
OCT7 

UC81* 



TRANSI STORS 

7/- OC84* 10/- 
S/. OC139 
SI- OCliO 

ocm 



12/- 
19/- 
10/6 



ocaxi 10/6 

OC201 21/- 

ocaa 14/- 

GET104 «/- 
. GBT105 10/- 
*Available in matched 



SERVICE TRADING CO. 

All Mail Orders also callers 
47 -4» High Street, Kingston on Thame* 

Tel : KTNgSton a*30 

Personal callers only 

'9 I Ittle NewDort Street, London, W.C.I 

!oawE3S?I?i»rt> Tel : GERl-ard 076S 



BCC * ITV • F.M. AERIALS 

B.BX. (BAND I). Tele 

scopii: loft 21/-. External 
hi/D 30/-. 

I.T.V. (BAND 3). 3 Ele- 
ment loft array 35/-. 5 
Element 35/-. Wall mount; 
Ing. 3 Element 36/-. a 
Element 45/-. 
COMBINED B.B,C.fI.T.V. 
Loft li-3, 41/3: l-i-S. 48/9- 
Wall mounting 1+3, 56/3: 
1+5, 63/9. Chimney It 3, 
63/9; 1+5. 7U3. 
rM. (BAND Z>. Loft S/D, 12/6. "H''> 
30K 3 Element. 52/6. External wnite 
available. Co -ax. cable 8cl. yd. Co-ax 

P'p^--. Seno BCL swmns for illustrated 
lists. 

K.V.A. ELECTRONICS (DeptP.W.) 

3b', Goditone. Road, Kenley, Surrey. 
CRO. 2S27 



NEW VALVES! 

Guaranteed Set Tested 

24-HOUR SERVICE 

ins 1S5 1T4 3S4. 3V4, DAF81, DP91, 
DK91 DL92 DL94 SET OF 4. 14/-. _, 
DAM6 DF96 DK96, DL96. SET OF 4. 82/-. 
riAo ^l/S DL35 6/- PCL82 6/3 

?£! %& Dlf2 4/3 PCL83 7/9 

ss 1/3 SmS 5/6 ?l* 84 m 

T4 03 E1M1 1/11 PLB1 6/6 

3S4 4/3 EBC41 ^J PLB2 5 - 

w3 =i/- EBFU0 6/- PIjSJ 5/- 

KraOT Si- ECC40 6/9 Pl^-i 5/3 

fz^g T 6% ECC81 3/3 m 8/6 

ffi J7 3 ECC84 5/6 PY81 5/- 

Rii-r fl/fl ECC85 6/- PY82 4/9 

ev«l 36 ECFSO 579 PYB3 5/6 

KV-SGT 5/- ECP32 5/9 U25 8/- 

VfKTCV 3/3 ECH42 7/3 U131 8/3 

WaGT 8 6 FCH81 5/3 US01 15/- 

1OT7CT la BCL80 5 9 UABCB0 5/- 

OT?SG 4/9 ECL82 6/3 UAF42 6/9 

WTl 7/9 EF41 6/6 UBC41 6/- 

a5L6GT 6/- EF80 3/9 UBF80 5/6 

35^4G? 4/6 EF86 5/9 GCC84 7/11 

On At <W8 EF89 4/3 UCC8S Bi- 

CL^ 8/9 EF91 2/9 UCF80 8/3 

DAC32 7/9 EL41 7/- UCH42 6/9 

Etpl II IyU ft TOL82 7?3 

B-^3 6 7/6 EY86 5/- UCL83 7/9 

S I/a E^Sl 3/1 UL41 6/6 

TlKsi 7/6 MUM 3/9 UL84 5/9 

DkI! 39 PCC84 5/3 URIC 5/- 
n^ fiifl PCC89 7/6 UT21 7/3 
S %1 PCFW 5/9 UY41 3/11 
dSb 6/9 PCF82 6/- U*BB 4/9 
Po^ta^e 6a. per valve extra. Any Parcel 
insLLred against Damage in Transit &d. extra. 
Any C.O.D. Parcel 4/3 extra. 
Office address, no callers, 

GERALD BERNARD 

83 OSBALDESTON ROAD, 

STOKE NEWINGTON, 

LONDON, N.l* 



2 METRES 4 

The thrills ol VHP Amatear Radio 
can now be yours tor as low as 39/6. 
complete kit (by post, carriage and 
packing, 2/6 extra). Tuning range 
70-150 Me/s. Stamped addressed 
envelope for free copy of literature 
and full details. Newcomers to 
Short-Wave Racia ask for details or 
the famous "Globe-King" kits and 
receivers, Home and Overseas Sales. 

JOHNSONS (Radio) 

St. Martins Gate, Worcester 



A.R,RX. RADIO AMATEURS 
HANDBOOK 1964 

New Edition 36/-. Postage 2/ a. 
Beginners Guide to Elet-troales, by 
U3fiMS£V *-V. Heeelv- 
gfe&Wffiirtg&t by Bradley. 

KS'aBd T.V. Handbook UH, 

by Johansen. 22/-. postage 1/;. 

How to Listen to tne World !»«. by 

Johansen, 14/6. postage 1/-. 

ABC's of Computers, by LJtel, 18/-. 

^mafeVr'ttadio Call Boot, by R.S.G.B.. 

1964 ed.. 4/6, postage Sd. 

Radio ' Amat fttir s Examination Manual. 

by R.S.G.B., 5/-. postage Bd. 

UNIVERSAL BOOK GO. 

12 Little Newport Street. London W.fll 

(.adjominsr ! .Ule Street) 




PRACTICAL WIRELESS 



391 






Tubes 



HIGHEST QUALITY — 
COMPARE DUB PRICES 



Our. * lus. ttm GUARANTEED 

I Months Lt Month, 

12in. £2. 0.0 £3. 0.0 
14in. £2.10.0 £4.10.0 
15 17 in. £3. 5.0 £4. 5.0 
21 in. £3.15.0 £5.15.0 



MOST MULXABD 
MAZDA. 0O88OB 
EMITROH, BMI- 
SCOPB, BRIMAK 
FEBBARTl TTPE8 
PROCESSED IS 
ORB OWB 
FACTORY 



NEW TYPES 
MW 81/47 

£3.15.0 

mw sb/S4 
£4.16.0 

CBM 17£ 

MW 43Jfi4 

£6.0.0 



GUARANTEED 

• VALVES • 

by return of port 
THE MOST ATTRACTIVE COMPETITIVE VALVE 

LIST IN THE COUNTRY 
All valves are new and unused unless otherwise advised 



SATISFACTION GUARANTEED 



EBCO L.O.P.T. Unused rci< lawmen fa 
W Perenex aaaed 1S54/7 model*, 
Mioapleto with K.H.T. reel, OQ / 



unrepeatable. 



CO-AX, low Iota, M. yd, 33 yda. 
11/8, 50 nto^ «*/-, 100 yd*., 42/9. 
Otf*x Plugs, ljj. Will outlet boxe* 3/8. 



■FECIAL C.R,T. OPTEB 
Due to hiin« Bulk special Purchase 
we are offering MW 31-74 Tube, at 
the uurepeauiile price ol 261- M"W 
Se'34 ditto. 19/.. p.p. ia/8. The 
abort are guaranteed for ft mouths. 



T-OCDSPEAB^':S. 

SSL- 7/6 



3 Q Top Makes. 

rtV 8/6 



CONNECTING WIRE 
3 VALVE AMPLIFIERS 

KB el new part*, «msa»ttn« chassis, 
SH^K? «•*»"* traaulonoert, valve* 
(Ml. SOea, 8X60) nod all aomponenls. 
wJin ftiu tawtructloo* Joe making high 
gain amplifier with separate bane and 
trabla oontroav Mplln feed. M / 
oaotetc. Truly unusual value at*«*/~ 

MAINS TRANSFORMERS 

*.xc*iieos Quality Guaranteed. 

! pri£bi mounting 2s(M)-26u V 
60 ni, 4.J V 1 A (90mA 12/S) n 10 
iXtto **a*i-*hre d*d a/a, 9/6 

13 CHANNEL T.V^ 

Tall, M uti k . haoai MaW. Asm- 
!»*•» Comsle**. These «w wToi 
^"wedjn value doe to huge purchase 
dirts* no Kuice, They are untested 
*af not guaranteed to be In working 
order, Oatr, etc, 1BK 

^£2.19.0 ltot £4.19.0 



TRANSISTORS 

Oil ABA STEED TOP QUALITY 
Hue* reduction. Bed Spot 1 /C 
standard Ljf. type aow only ■ / " 

Whit* spot bj. n I 

Mallard Mitohed Output Bit! -in Id 
(X'SlIt and 2-OC81. 1 at / D 

R.F, Kit* (OC4A 004B (ii). 1 1) fe 
3 Irajiaislois. lA/Q 

AP114 8/- 0C44 

ATM 7/8 OC45 

AFllfl 7/8 OC78 

AJU7 7/- OC81 

AP187 9/8 OC81D 

joea ig/e ocsa 

JC33 14/. OC170 

OC171 S(8 

GERMANIUM DIODES 

General Purpose miniature detector , 
A.V.C, etc « j 

or 8/8 doi. OU . 

Gold Bonded highest quality, 
vlrtially tested. 
9/8 dox. 

SILICON RECTIFIERS 

Guam teed peifonnanee. Ton Make 

Tested 'J50V working 

lUOuiA <% In SStaA 

,3 for 9/fli «/« is for lfl/8) 



POST 

1 VaJre Si, 8-11 

FREE [ar IS or 
lalves. 



3 MONTHS 
GUARANTEE 

In writing with 
erery yalye. 



PRBB IEAKSIT IH- 
SURANCE. Satisfaction 
or Money back Ouaj-iu,- 
tee on Goods II refurr.etl 

within 14 iijv(. 



FALYE HOLDERS. B7B, 84, ea^ with 
Ssreen Bd, ea., BHA 64 ea., with Serpen 
3d. ea. bat. Octal 84. Maade Octal 4d. 
USA Bd, lies* 13% in licuen*). 



TURRET TUNERS 

Most makes, yonr choice Ii avail- 
aljle, with valve 18/., teas valve* 
If-. S.A.K. enqulrtej>. 



LBAK AMTLITIEB IfTIPS 
"«»• tortanat* mehua v* an able 
*°. ™*» «» !oUowin» nnrepeataiile 
arAra. AH uriUtn safe line matehbr 
■rP^ T ™ utwnl • r, (TMMtormert to 
mateh shwt Amplifier! to 16 Speaker! 
2",i? WtpUed al me eaeh). 

TL/B6 WATT (new) fis 

Sou— The*. Lmk Ampllflen atl hive 
*5»dd«d IteUlty ol ealamt and tone 
controls 10 that they eaa a* ua*d without 

* are-amp. It »ry high iiu ii not 
r« Haired, 

• SULK BARGAINS ^ 

IB POTS, Popular value*. 6K to 
2 Meg. riiuaed mJied. pre. * la 
wi, limg ni. switch, etc. **/P 
COrTDESSERS. 25 Sfixad. Electrolvtic. 
S'any popular aiie*. Ur* 
^ aine is. Our prior 

100 RESISTORS 

E tee Dent, aiaai. J. 3 watt. 

100 CONDENSERS 976 

Hluiatu« Centuic and Silver Mica 

25 TAG STRIPS 4/- 

;, 4, fl, a way e to. Unaaed. 

100 HI STABS 9/6 

% w B "'. lOn n in imo. 



0OSSOB D.B. STOPS TUBES. Tyne 
W* fv' 1 ' Beam. Ideal for uulldinpt vour 
iwii iiuaHty oe&uoijcope whltet BB I 



slock, taut.' 



LINE TRANS. 

Hus» quantitr mini makes 



S.A.B, euqoiriea. 



ai onty flQ l m 



10/- 

6/6 



RECTIPTEHS. 250 v., tW mA. 5/- 
RMi; B/B; HM3, 7/6; HM4. 19/8; KM.'., 
19/8; 14AS6, 17/-: UAS7, IS/8; 
MA100, iB/ej MHC1-I-18-L 7/B; 
IbBAl-l-l-ifj-i. 8/-; lBR02.a-g.l, 14/-; 
Li^-W-i 17(-; 14BA1-SM-8, 80/-; 
ELECTRIC MOTORS. AC;i>C U 
Tolte. Totally enclosed standard 
mounting, tiowerfai V pulley 
*Dare hrrahes, an. i an. 



AM/FM RADIOS 

Pantoetlc oiler, 7 valves pros 
'i diihli!*. Contemporary Cabinet, 
Top qaallty ami finish. A.PJi 
A.V.C. Absohtely eomD- *4 
oiete. Guaranteefi ? month.. ' ■ gn» 



rNQUIRlBii WELCOMES 
Qnantlty Price! or Quotes 'or Iteri* 
ool Wad , nartlenlarly rare value*. 
TELEPHONE C.O.D. ORDERS 
TMKWATfmi THF SA^P DAY. 



TECHNICAL TRADING CO. 




CO^K Ef - extras ALL ITEMS LE8H 6% ASD POST FRKE IN DOZES8. 
»erL-.« E HH0PS KETAfl. OS' V 

75 p Fratton Road, Portimouth fTeljM03d) 
'2 east Strea*. Southampton fT«i: 258SI, 

ALL MAIL ORDKH KK'iAlI. SHOP AM- HJ-E1 Rnnin 

11-12 NORTH ROAD, BRIGHTON. Teh67W 



392 



PRACTICAL WIRELESS 



August, 1964 



We supply from stock most of 
the components and items speci- 
fied or circuits published in this 
and other magazines and radio 
books. Let us quote for your 
circuit, first grade components 
at realistic prices. 



TRANSISTOR TRANSCEIVER 
Two way Trans, receivers. 9-Transistor 
superhet circuit, crystal controlled on both 
transmit and receive. Push-pull output. 
Ranee up to 5 miles under best conditions. 
Supplied complete with batteries, Telescopic 
aerials and leather cases. Overall sizes; 
64 x 3 x \i inches. Sold in pairs. 
PRICE PER PAIR £25. P.P. 3'-, 



CATALOGUE 

Now 86 pages fully 
detailed ana illustrated 
with hundreds of new 
items and bargain*. 
PRICE 2'6. Post Paid. 



DEAC RECHARGEABLE 
BATTERIES 
18 volt lOOmA'H 4 x I in. diameter. 
Brand new sleeved, 30'-. 
3.9 volt 450mA H, 12'6. . 

All types easily split into any multiple 
of 1.2 volt. Brand new. 



MULTI-METERS 

Multi-range test 
meters featuring easy 
to read scales and 
provided with full 
operating instruc- 
tions, lead and bat- 
teries, Suitable for 
amateurs, designers, 
repair shops, all do- 
mestic uses. Full 
details and specifica- 
tion in our catalogue. 

I Kohm/volt £1 19 6 

„ _ £2 9 6 

„ (illus.) £3 IS 

. £4 9 6 

„ £5 5 

" £5 19 6 

£6 19 6 

£8 19 6 

" ...,. _ £9 19 6 

Leather Cases available. 

NOMBREX TEST EQUlPMENTj 




LEAFLETS 

ON 
REQUEST 



All transistor 
portable units 
supplied with 
full ins t ruc- 
tions. 

+ 150 Kc,'s to 3M> Me's generator. RF, 
Mod., AF. 8 ranges. Leads, batt., 
instructions, £9.10,0. 

if Resistance/ Capacitance Bridge. £8.5.0. 

if Transistorised Power Supply. £6.10.0. 

it Audio Generator, £16.15.0. 

ic Inductance Bridge, £18. __ 



QUARTZ CRYSTALS 

100 Kc's 3 Pin 15 '• ea. 

500 Kc s 2 Pin ■15'- 

455 Kc s (AR88) «'* 

5000 Kc.s 2 Pin — ° * 

10 Mo's 2 Pin | ■ 

27 Me/s Radio Control J» - 

456 Kc/s HRO — ■■■■■} s '- 

Twin Marker Crystal I Mc/s and 100 Kc.s. 

Over 600 Frequencies in Stock for 
all purposes. Catalogue on request,) 
MAINS AND' BATTERY 
RECORD AND TAPE DECKS 
All Decks Complete with Cartridges 
if BSR UAH 4-speed Auto ... £5 16 6 

if BSR UA15 4-speed Auto £6 19 6 

-*■ Garrard Autoslim Auto £6 10 

-£• UnplugableHd. Versn. Auto. £6 19 6 

ir Stereo Version Auto. - £7 " ■ 

■^ SRP10 4-speed Single Player £5 5 
-+• BSR GU7 4-speed Single 

Player - - £5 

if Garrard AT6 with Stereo 

Cartridge Autoehanger ..... £10 19 o 

if AT6 Mono •■• '• !«■ 

■J Collaro 2-traek Studio Deck £10 10 

* 4-traek Deck - £13 19 6 

P, & P. 3'6 any type above, 

•fc 9 volt Starr, 45 r.p.m *9'6 

I 45 or 33 r.p.m, Starr 9V «'* 

•+■ 45 r.p.m. Garrard, 6V ......35'- 

£• 4-speed B.5.R. 9V * gns. 

ir Garrard 9V, 2-speed, 2-track 

Tape Deck with casette. „.£l I 15 U 

p. & P. 2 f 6 any of above. 

SUBSTITUTION BOXES 

Capacitor Box. 0.001 to 0.22 mfd„ 19'6, 
• Resistor Box. 15 ohms to 10 meg., 
37'6. 



IS' . 

Crystal ( 

I 



Stereo Stethoscope Headset 
m Mono Stethoscope Types. 

10'6. Magnetic I2'6. 
Fully Retractable Car Aerial— Thiel ( 

Proof, 39 '6. 
PP3 Battery Eliminator, I8'6. 
m Tape Demagnetiser, 29'6. j 

m IK ohm Dynamic Microphone, IV*. i 
% S-i-Sohm Stereo Headphones, 62'6. 
m Transistor Signal injector, 39 '6, , 

Crystal Ovens, 6/ 12 volt. 22 '6. , 

• 12 inch 15 ohm Speaker, 35'-. , 

% DFI dynamic Mic. 50 k, with stand, 51'o , 

New range in stock. See catalogue. : , 
9 5-Piece Hole Cutter for all chassis work , 

£in. to I |in. with pouch, 49'6. 

• gef ° y — .^ gTriw p.p. «d. ; 

S2K, i-track Tape Head 15'- P.P. 9d. 
Telephone Recording nj ( 

Attachment — __ „I2'# r.l* 

4-Channel Transistor Mixer 



M. 



TO BUILD YOURSELF 

Sinclair TR750 Amplifier 

Sinclair Micro-6 

Sinclair Micro Injector 



_39'6 
S9'6 
.27 '6 



Unit 

Tape Jack Radio Tuner 



FOUR TRACK Total 
Cost 

ALL AUDIOKITS IN STOCK 
Leaflets on Request # 

• 4 Transistor 9 volt, 3 ohm, I watt. 

Amplifier Built 

Kit 



HI-FI SPEAKERS 

CX300 12 inch 25 watt 
CRI2AE 12 inch 20 watt 
CR30AE 12 inch 20 watt 
triple range 

8A7 8 inch 6 watt 

10 watt Horn Tweeter 

20 watt Rect. Horn Tweeter 



12 Gns. 
8 Gns. 

10 Gns. 
79'6 
29'4 
69 '6 



Leaflet and details on request. 
AH parts in stock for 9 volt mains 
power pack, PVV Inverter and 
Build and Learn series. Please 
send full list of parts required 
for quotation. 



MINIGRAM TRANSISTOR 
PORTABLE RECORD PLAYER 

9 Made by well 
known British 

manufacturer. Fea- 
tures ready built 
4-transiscor 
printed circuit I 
watt am p I i fi e r, 

elliptical speaker 
and volume con- 
trol. Low current. 
Starr constant 

speed 45 r.p.m. 
turntable with 

crystal pick-up. 
Strong moulded two colour cabinet with 
handle. Plays anywhere on long life 9 
volt battery. Requires less than hall an 
hour's. work to connect up using ready 
built units and easy instructions, 
TOTAL 70 /ft pp - 
COST "'""S'- (Battery 3'9). 
Or Amplifier with volume control and 
5 x 3 inch Speaker, 4-Transistor, 35'-. 
P.P. 2'-. 

9 volt Starr Player with Pick-up 39'6. 

P.P. 2'6. And Two-Tone Case 5'-. P.P. 2'-. 

«,«,»^^ » » » » »«■»» »*»»»» ** 




ALL PARTS IN STOCK FOR 
PW SHORTWAVE TRANSIS- 
TOR CONVERTER. As per Feb. 
Edition 1964. 



CRYSTAL MICROPHONES 

Acos 39-1 Stick Microphone — -32'6 

Acos 60-1 Stick Microphone -27'6 

Acos 40 Deck Microphone.....™ -15 - 

Acos 45 Hand Microphone — -22'6 

Lapel I Hand Microphone.™,... 1*6 

100C Stick with Stand -J''* 

BM3 Stick with Stand... 49'6 

L apel Hand Magnetic — a'P 

MINIATURE PANEL METERS 
*0'50'iA (D.C.) 39'6 *0 5mA (D.C.) 27'6 
•O/SOOuA (D.C.) 32'6 *Q/300V (D.C.) 27'6 
♦0/lu.A (D.C.) 27 '6 ''S" Meter 35'- 

All Brand New Boxed. 'Available Clear 
Plastic Front or Black Moulded. 

200ttA D.C. Edge meter 69 6 

1 niA D,C. Edge meter..- _, S9'6 

3 j x I inch Front Panel, 

POCKET SOLDERING IRON. 30 
watts, 220/250 volts A.C. Complete with 
pointed bit, mains plug, carry pouch. 
I4'6. PP. 1'6- 



59'6 P.P. I '6. 
...19>. P.P. I'-- ,, 

"MARTIN RECORDAKIX.o, c I 
BUILD A QUALITY PORTABLE 

TAPE RECORDER . ', 

Complete in every detail. « Pre-buit| 
u nits—Col laro Stuoio Decks— Portable 
Cabinets with speakers. 6 valve designs. ' 
TWO TRACK Total gjg^Q «■{, 

£30.0.0 S£|j 

I 
I 

49'6 
39'6 

Xtal controlled ( i 
4 mile. Price 
I 
I 

FIELD STRENGTH METER I 

Five channels cover I Mc to 200 Mc/s. , I 
Fitted 200 microamp meter for CW or t 
RF. Indication and Earphone lor A.K § 
Monitoring. Designed for checking all,' 
types of transmitters. Sue 4 x 2f x 2*in. i 
Complete. Ready to Use, with instruction i 
and telescopic aerial, *»'6. Post Free, j ■ 

PP3 9 volt Battery Eliminator '8'* , 

% 3 Transistor MW Superhet Tuner 82'6i| 

• 4 Transistor MW/SW Superhet ! , 
Tuner ".9.6 

• BM3 Stick Xtal Mic with Stand...- 49'* ( 

100 C Stick Xtal Mic with Stand 39'6< 

• 8A7 15 ohm 6 watt Hi-Fi Speaker 79'4 1 , 

(I 



% New 3-Transistor. 
Transceivers. Up ti_ 
per pair, £8.19.6. P.P. 2'6. 



7in. 
7in. 



RECORDING TAPE 
5in. 600ft. 12'6; Sin. 900ft., 15J-J 
I 200ft„ I8'6; 7in. 1, 800ft., 25'-; 
2' 400ft., 27 '6. Excellent quality. 
• 3 inch square 3 ohm Speaker, I2'6 



TEST LEAD KIT supplied in Pocket i| 
Pouch. Contains probes, leads, clips, etc. ' | 

• EMI 2i inch Plastic Cone Tweeter' 
3/5 ohms, 17'6. P.P. 9d. J 

% New 6 pole 2 way Miniature Push' 

Switch, 6'-. J 

HEADPHONES 

2000 ohms 12'6. 4000 ohms 14>- , 1 

Henry's Radio Ltd. 

PADdington 1008/9 
303 EDGWARE RD„ LONDON W.2 ' 

Open Monday to Sat. 9-6. Thurs. I o clock. 1 ■ 

il 



PLEASE TURN TO BACK PAGE 



»>i >»» »* ^ » * » ■ * ■**•*' 












August, 1964 



PRACTICAL WIRELESS 



Practical Wireless 



BLUEPRINT 
SERVICE 



flLL of these blueprints are drawn full-size and although the issues containing descriptions of these 
sets are now out of print, constructional details are available free with each blueprint excebt 
for those marked thus (*), r 

^t { ?^ rC l b Jl)c a Jcr tQl ° rder t0 COV€r the cost °f the Blu(i P rint (stamps over 6d. unacceptable) to 
WRACTICAL WIRELESS, Blueprint Dept., George Newnes, Ltd., Tower House, Southampton Street, 

London W.C.2. r 



DOUBLE-SIDED BLUEPRINTS 

Each blueprint in this series contains details of 
^separate instruments or items of equipment. 

The Strand Amplifier 
The PW Signal Generator 

The Savoy VHF Tuner ., 
The Mayfair Pre-amplifier 

The Berkeley Loudspeaker Enclosure i 
The Luxembourg Tuner 

The PW Troubadour | 

The PW Everest Tuner 



The PW Britannic Two 
The PW Mercury Six .. 



:::}• 



The PW Regency ■ 

The PW International Short Wave Two f 



RECEIVERS 



The Tutor * 

The Citizen * 

Junior Crystal Set 
Dual-wave Crystal Diode 
Modern One-valver 
All-dry Three .,. 
Modern Two-vaiver 
A. C. Band-pass Three 
A.C. Coronet-4 
A.C. D.C. Coronet 
The PW Pocket Superhet 



PW94 

PW95 

PW96 

PW97 

PW98 

PW99 

PW 1 00 

PWIOI 



two 

S'- 

5'- 
5'- 
7'6 

6'. 
5'- 



5'- 

2'- 
2 '6 
2'6 
3'6 
V6 
4'- 
4'- 
4'- 
5'- 



MISCELI ANEOUS 

The PW 3-speed Autogram 

The PW Monophonic Electric Organ 

The PW Roadfarer « 

The PT Band III TV converter 

The Mini-amp * 

The PT Olympic * 

The PT Multimeter * 



8'- 
8^- 

5'- 
l'6 
5'- 
7 '6 
5'- 



SOME EARLIER DESIGNS 

THE following blueprints include some pre-war 
I designs and are kept in circulation for those 
constructors who wish to make use of old com- 
ponents which they may have in their spares box. The 
majority of the components for these receivers are no 
longer stocked by retailers. 



Experimenter's Short Wave 
Midget Short Wave Two 
Simple S.W. One-valver 
Pyramid One-valver 
BBC Special One-valver 
A One-valver for America 
Short-Wave World Beater 
Standard Four Valve S.W. 
Enthusiast's Power Amplifier 
Standard Four Valve 
Listener's S-Watt Amplifier . 



PW30a 

PW38a 

PW88 

PW93 

AW387 

AW429 

AW436 

WM383 

WM387 

WM39I 

WM392 



2 '6 
2 '6 
V6 

2 '6 
2'6 
2 '6 

3 '6 
3 '6 
3 '6 

V6 
V& 



QUERY < Ol l»0\ 



I 

This coupon is available until 7th August. 1964. ' 
and must accompany all queries in accordance I 
with the notice on our "Letters to the Editor" | 
page. 
PRACTICAL WIRELESS, AUGUST, 1964. 



mp g M^Mrffi^ ^» ^ra^^^S^'r^Jl^r* ^..London. W.C.2. and 






PRACTICAL WIRELESS August 1964 



TRANSISTOR HIGH FIDELITY EQUIPMENT Z™™™^ 

MAINS OR BATTERY OPERATION. 3 AND 15 OHMS. | , ■ 




I # MONO PREAMPLIFIER AND CONTROL UNIT. 

For use with either of above amplifiers or valve amplifier! 
" — Hjm Free — High Sensitivity — 8 Inputs between I.SmV 

and 300mV. For all pick-tips — Microphones, Tunen — Tape 
. Replay. Separate treble and bass with cot and boost — 4 position 
'Low Pass Filter — Volume etc Panel size 9 x 2*in, Battery 
''operated or from power supply. 

|l ~ 



10 WATT POWER AMPLI- 
FIERS. r'Two versions. ± IdB 
40 c'rto 20 kc/s. 60dB Feedback 
lOQVnV input and less than 0,25 „ 
distortion for 10 watts output. 
3 and 15 ohm versions. Very low 
current. ©-Transistors and Recti* 
fier. 

* 3 ohm 10 Watt. • 15 ohm 10 Watt. 

BUILT £5.10.0 BUILT £5,19.6 

P.P. 2'6. R.P- I'o- 

■jV MAINS UNIT — will run 2-amplifiers for 3 ohm and ■ 

15 ohm. 69'6, P.P. 2'$. Each typo. 
•fa Mains Unit lor single amplifier, 59'i. P.P. 2'-. 
9 Preamplifier Built. 

£5.10.0 ppi' 




Low Distortion. f 
# High Performance. ♦ 
Mains or Battery. { 
Low Noise Design. 
Mono or Scerecflj 






Dark Brown and Gold 
Panel Plate. B'o. 

GUARANTEED HIGH* 
PERFORMANCE UNITS. # 



I COMPLETE CIRCUIT5 

: WITH FULL DETAILS 

ON REQUEST 



Trade 
Available. 
Details, 



Discounts! 
Send For I 




PREAMP 



STEREO TRANSISTOR INTEGRATED 

PRE-AMPLIFIER AND CONTROL 

UNIT 



* 

♦ 

ii ♦ 

::■• 

j 
I 
I 

♦ 

♦ 
I 



Simplified version of Mono 
Preamp above. 8 inputs as 
above. Input selector, Tone 
and Volume Controls. Site 

5 x 2i x 2in. Ideal as a Preamp 
for any valve or Transistor 
amplifier. 
PRICE BUILT . P.P. 



65/- 



Dark Brown and Gold Panel Plate & f 6 

LOW DISTORTION 
HI Fl • 



HIGH PERFORMANCE 
LOW NOISE 



# Low noise printed 
circuit design develo- 
ped from above mono 
equipment, 

Ganged controls, 8 

inputs per chai 

all types of input. 

Treble, bass, volume 

selector, on off mono-stereo, 

etc. 

£ Designed for use with either 

of above 10 watt amplifiers. 




# PRICE BUILT 

£10.19.6 

Dark Brown and Gold 
P^nel Platen 12'*. 



CONVAIR' 



w* 




V ALL PARTS SOLD SEPARATELY 
1 - (Batteries e-'- extra). 



PUSH-BUTTON 
PORTABLE CAR RADIO 
• New printed circuit 6-Tran- 
sittor design. Over 700mW 
push-pull output. 
'0 Push-button selection of MW 
and LW with full tuning on 
both wavebands.. 
% A new design with amazing 
performance at a realistic 
price. 
New attractively designed por- 
table cabinet with horizontal 
tuning and all stations marked. 



VHF FM TRANSISTOR TUNER 



Total Cost of ALL Parts 

£7.19.6 K 



{5-Transistor. 
High Sensitivi- 
ty, 
#4 Diodes. 
>0 Full coverage 87 
1 1 tolOSMcs. 
i « AFC and AVC. 
1 1 # Up to I volt 
1 1 output. 
1 1 Printed circuit de- 
i ' sign of high sensiti- 
i vity and quality. 
i 1 Output for valve or 
i > transistor" amplifiers. 
'Size 3J x 2| x 4in. 
Simplified building 
instructions. All 

l > parts sold separately 




Detailed Circuit Book on Request. 



'# FOLLOWING A LINE OF QUALITY AND VALUE IN PORTABLES 
^^^-t.-^a-m ».«.«.».■*»»■» ■a-»'-»-i-s-»-i'i-~ ------ --- — .» I 

I 7-TRANSISTOR RECORD PLAYER RADIOGRAM AMPLIFIER^ 

^--43L_ aesa. • Mains or Battery operation. '0 SCOTCH BOY TAPE. 3J-in., 300fc 

plcto with spare spool. S'e. P.P. 9d 




_ 4 watt peak output 

# Full Treble and Bass boost and cut. , 

* 40 cs to 20 kc s • 3 dB. 
Inputs lor Pick-ups. Radio Tuners 

Microphones, mixers. 
9 9 12 volt for 3 ohm speakers, 
(mains unit 49'6 extra). 



Bu.U Ready £C 1 6 ?, P - 
To Use u ' ,7,g V-. 



_ Site only 6 x 2J x 21n. 
I Ideal for mains or battery, portable or 
I domestic record player, grams, etc. 



Latest 86-page fully detailed 

and illustrated catalogue. Com- f 

ponentt, accessories, Hi-Fi equip' 



'domestic recoru pu;n, 6'="'». -~- ■ ■ — -z,r , _-j 

tOrcar. ment, etc. 2'6 post paid 



TOTAL f-f IQA 
COST t'.IT.W 



P.P. 
2*6. J 

(Cabinet assembly 20'- extra.>j 



L.P. 



edWCTJ 

I « MARRIOT TAPE HEADS. Type R RP 3. i" 
I track Compete with Mullard P. MAG. erase 

ring. IS'-.' P.P.. 1'-. The pair. 
>»»« » **.»»«*»» * *»» » * * *« « * I 

I _ ___ 

ngton 1008 9.i 



HENRY'S RADIO LTD. «** 

303 EDGWARE ROAD, LONDON W.2. 

(Open Monday to Saturday all day 9 a.m. to 

6 p.m. Half-day Thursday I p.m.). 
PLEASE TURN TO INSIDE PAGE